The Functional Lines

Overview

The Functional Lines (Fig. 8.1) extend the Arm Lines across the surface of the trunk to the contralateral pelvis and leg (or up from the leg to the pelvis across to the opposite rib cage, shoulder, and arm, since our meridians run in either direction). One of these lines runs across the front of the body, one across the back, so that the right and left lines together form an ‘X’ across the torso (Fig. 8.2/Table 8.1). A third line in this group, the Ipsilateral Functional Line, runs from the shoulder to the inside of the same knee. These lines are called the ‘functional’ lines because they are rarely employed, as the other lines are, in modulating standing posture. They come into play primarily during athletic or other activity where one appendicular complex is stabilized, counterbalanced, or powered by its contralateral complement. An example is in a javelin throw or a baseball pitch, where the player powers up through the left leg and hip to impart extra speed to an object thrown from the right hand (Fig. 8.3).

Table 8.1

Functional Lines: myofascial ‘tracks’ and bony ‘stations’ (Fig. 8.2)

Bony stations		Myofascial tracks
Back Functional Line
Shaft of humerus	1
	2	Latissimus dorsi
	3	Lumbodorsal fascia
	4	Sacral fascia
Sacrum	5
	6	Gluteus maximus
Shaft of femur	7
	8	Vastus lateralis
Patella	9
	10	Subpatellar tendon
Tuberosity of tibia	11
Front Functional Line
Shaft of humerus	1
	2	Lower edge of pectoralis major
5th rib and 6th rib cartilage	3
	4	Lateral sheath of rectus abdominis
Pubic tubercle and symphysis	5
	6	Adductor longus
Linea aspera of femur	7
Ipsilateral Functional Line
Shaft of humerus	1
	2	Latissimus dorsi, outer edge
End of ribs 10–12	3
	4	External oblique
Anterior Superior Iliac Spine	5
	6	Sartorius
Pes anserinus, medial tibial condyle	7

Fig. 8.1 The Back, Front, and Ipsilateral Functional Lines.

Fig. 8.2 Functional Lines, tracks and stations.

Fig. 8.3 The Functional Lines add the impetus of the trunk momentum and musculature to the strength of the limbs, stabilized by the contralateral girdle. In this instance, as the arm is drawn back to throw the javelin, the right Back Functional Line is contracted, while the right Front Functional Line is stretched and readied for contraction. The left FFL is lightly shortened, and the left BFL lightly stretched during this maneuver. When the javelin is thrown, all these conditions reverse – the right FFL contracts, the right BFL is stretched, and their left-side complements exchange stabilizing roles.

Postural function

As mentioned, these lines are less involved in standing posture than others under discussion in this book. For the most part, they involve superficial tissues that are so much in use during day-to-day activities that their opportunity to stiffen or fascially shorten to maintain posture is minimal. If they do distort posture as a whole, their action is to bring one shoulder closer to its opposite hip, either across the front or across the back. Although that pattern is common – especially closing across the front – the source for it usually resides in the Spiral Line or in deeper layers described in Ch. 9. Once these other myofascial structures have been balanced, these Functional Lines often fall into place without presenting significant further problems of their own.

These lines do, however, have strong postural stabilizing functions in positions outside the resting standing posture. In many yoga poses, or postures that require stabilizing the upper girdle to the trunk (as, for example, when working above the head), these lines transmit the strain downward or provide the stability upward to fix the base of support for the upper limb. Less frequently, they can be used to provide stability or counterbalance for the work of the lower limb in a similar way, as in a football kick.

There is but one common postural compensation pattern associated with the Functional Lines and that is a preference rotation usually associated with handedness or a specific activity such as a sport, where one shoulder draws closer to the opposite hip repetitively. This can affect the tonus and coordination of all six Functional Lines, but the Spiral, Lateral, or Deep Front Lines are usually the more salient limiters to the pattern.

Movement function

These lines enable us to give extra power and precision to the movements of the limbs by lengthening their lever arm through linking them across the body to the opposite limb in the other girdle. Thus the weight of the arms can be employed in giving additional momentum to a kick, and the movement of the pelvis contributes to a tennis backhand. While many applications to sport spring to mind when considering these lines, the mundane but essential example is the contralateral counterbalance between shoulder and hip in every walking step.

The Functional Lines appear as spirals on the body, and always work in helical patterns. They could be considered as appendicular supplements to the Spiral Line, or, as stated above, the trunk extensions of the Arm Lines. In real-time activity, the lines of pull change constantly, and the precision of the lines detailed below is a summary of a central moment in the sweep of forces.

The Functional Lines in detail

The Back Functional Line

The Back Functional Line (BFL) begins (for analytic purposes; in practice it connects in with the Superficial Front or Deep Back Arm Lines, depending on the particular action) with the distal attachment of the latissimus dorsi (see Fig. 8.1A). It runs down a little lower than the approximate center of that muscle's spread, joining into the superficial laminae of the sacrolumbar fascia.

The BFL crosses the midline approximately at the level of the sacrolumbar junction, passing through the sacral fascia to connect with the lower (sacral and sacrotuberal) fibers of the gluteus maximus on the opposite side.

The lower fibers of gluteus maximus pass under the posterior edge of the iliotibial tract (ITT), and thus under the Lateral Line, to attach to the posterolateral edge of the femur, about one-third of the way down the femoral shaft. If we continue on in the same direction, we find fascial fibers linking the gluteus and the vastus lateralis muscle, which in turn link us down through the quadriceps tendon to the patella, which is connected, via the subpatellar tendon, to the tibial tuberosity. We choose to end the line analysis here, though, having reached the tibial tuberosity, we could continue this line down to the medial arch by means of the tibialis anterior and the anterior crural fascia (as discussed in Ch. 4 on the SFL).

The Front Functional Line

The Front Functional Line (FFL) begins at about the same place as its complement, with the distal attachment of the pectoralis major on the humerus passing along the lowest fibers of that muscle to their origin on the 5th and 6th ribs (Fig. 8.1B). Since the clavipectoral fascia containing the pectoralis minor also connects to the 5th rib, the FFL could be said to be an extension of both the Superficial and Deep Front Arm Lines.

These pectoral fibers form a fascial continuity with the abdominal aponeurosis that links the external oblique and rectus abdominis muscles, and the line passes essentially along the outer edge of the rectus or inner edge of the oblique fascia to the pubis, a strip of fascia known as the semilunar line. Passing through the pubic bone and fibrocartilage of the pubic symphysis, we emerge on the other side with the substantial tendon of the adductor longus, which passes down, out, and back to attach to the linea aspera on the posterior side of the femur.

From the linea aspera we can imagine a link to the short head of the biceps, and thus to the lateral crural compartment and the peroneals/fibularii (Spiral Line, Ch. 6, p. 141). This, however, would involve passing through the intervening sheet of the adductor magnus, which is not allowed by the Anatomy Trains rules. We will therefore end the FFL at the end of the adductor longus on the linea aspera (see Fig. 2.5).

The Ipsilateral Functional Line

The Ipsilateral Functional Line (IFL) follows the most lateral fibers of that most lateral muscle, latissimus dorsi which attaches to the outer portion of the lower three ribs (Fig. 8.4), with a strong fascial fabric connection to the posterior fibers of the external oblique, the same fibers employed in the Lateral Line in Chapter 5. If we follow the external oblique we arrive at the anterior iliac crest, where fibers connect fascially over the ASIS to the sartorius muscle (see Fig. In. 22A). The sartorius takes us down to the pes anserinus, on the medial epicondyle of the tibia.

This line can be felt when supporting the body on the latissimus as on the rings, or a circus performer aloft on silks, or on swimming when pulling the hand down through the water in a crawl stroke. Hanging from a chinning bar or a tree branch and twisting the pelvis and legs will also bring this line into your awareness.

Discussion Forces in motion

Our description of these lines required several approximations, not only because of individual differences but also because movements along these lines often sweep across fans of muscle and sheets of fascia. In other words, bringing back a javelin for a throw will pass through the precise BFL only for an instant as the force sweeps from the lateral outer edge of the latissimus around to its upper inner edge. Hurling the javelin a second later will likewise occasion a sweep of force across the fans of the FFL in the pectoralii, abdominal obliques, and inner thigh muscles (see Fig. 8.3).

Let us illustrate the versatility of these lines with a tennis volley. The serve involves a sharp pull directly along the FFL involving principally the pectoralis major, but perhaps also the pectoralis minor in a connection to the abdominal muscles, whose sharp contraction adds to the force and the expulsion of air and sound that often accompanies the serve, and finally the adductor longus or its neighbors who act to keep the abdominals from pulling the pubic bone up (Fig. 8.5).

Fig. 8.5 The Front Functional Line in a tennis serve. The stronger and more vertical the serve, the more the Superficial Front Line will also participate in driving the ball.

The return shot a moment later might be a straight forehand shot, with the arm out relatively horizontally from the shoulder. In this case the linkage would go up the Superficial Front Arm Line from the palm that holds the racquet, to pass from one pectoralis across the chest to the pectoralis and Superficial Front Arm Line on the opposite side (Fig. 8.6). This connection can be felt across the chest in such a shot, or observed in the movement of the opposite arm forward to help impart momentum to the ball.

Fig. 8.6 A tennis forehand connects the Superficial Front Arm Line to its partner directly on the opposite side – one of several angles that the arms can transmit force to the front of the torso.

The backhand required a moment later could pass across from one latissimus to the other along their upper edges (Fig. 8.7). A forehand to the opposite corner might be carried across the body, essentially on the Spiral Line, to the opposite anterior spine of the hip. Alternatively, Figure 8.8 shows another route crossing over from the Spiral Line to the FFL. A high backhand to return a lob might require the entire latissimus. The rest of the volley might go diagonally down and across as we have detailed with the BFL, or straight down the Superficial Front Line for a point-winning slam right at the net.

Fig. 8.7 A backhand shot could similarly join the latissimus to its opposite partner as well as down the torso to the pelvis and beyond.

Fig. 8.8 As an example of the sweep of forces, consider the sheet of the external oblique **(A)**, whose upper fibers all start from the ribs, but with various lower attachments. The lateral fibers go to the ipsilateral hip bone (part of the Lateral Line), the middle fibers go to the pubic bone (and on into the adductors on the opposite side), essentially a branch of the Functional Line shown in **(B)**, while the upper fibers cross via the contralateral internal oblique to attach to the opposite hip bone (Spiral Line). Thus the Functional Lines, the Spiral Line, and the torso portion of the Lateral Line all lay claim to part of the external oblique, and could be grouped as the ‘helical’ lines, as opposed to the Superficial Front and Back Lines, and the Lateral Line taken as a whole, which constitute the ‘cardinal’ lines.

For another example, imagine a vaulter levering off the pole: the force flickers across the entire triangular field of the pectoralis or the latissimus, linking and anchoring to various tracks and stations in all three of these lines from second to second. In this example, the stability–mobility equation is reversed, with the shoulder stabilizing the body on the pole, and the hips and legs imparting momentum over the bar. If we add the deltoid–trapezius connection from the Superficial Back Arm Line we see an entire circle of stabilization around the shoulder joint, any piece or all of which may be called upon during the vault (see Fig. 7.13, p. 160).

The lower end of these Functional Lines works in the same way. In a hurdler, the forces approaching the roundhouse of the pubic bone from above sweep around the fan of abdominal muscle, and from below along the fan of adductors.¹

Depending on his relation to the hurdles, and how much he abducts his leg to go over them, the line of pull from pubis to leg might travel on the pectineus, or any of the adductors, more than likely sweeping through all or most of them during each leap. In this case, the anteriority of the opposite shoulder works through this line to give added impetus to the leading leg (Fig. 8.9).

Fig. 8.9 The forces going through the hurdler's body cross the Front Functional Line only at one moment during the leap, but a connection between the forward leg and the opposite shoulder is maintained throughout the movement.

From this, we hope the reader grasps the idea that while the Functional Lines present the idealized line, the actuality of moment-to-moment movement flickers across the body from motor unit to motor unit on a multiplicity of connections combining the Functional, Spiral, and Lateral Lines.

Palpating the Functional Lines

For both the Front and Back Functional Lines, we begin in almost the same place: in the armpit, on the underside of the humerus, where the tendons of the pectoralis and the latissimus come together. Have your model standing with his arm straight out to the side, pressing down on your shoulder. It is easy for you to trace both these tendons from either side of the armpit up onto the antero-inferior aspect of the humerus.

Taking the BFL first, we can trace it from this attachment across the lower third of the latissimus directly to the midline at about the sacrolumbar junction. Have your model press an elbow down against resistance to feel this lateral part of the latissimus, though the line itself runs a bit medially from the lateral edge (DVD ref: Functional Lines, 19:19–22:39). The main sheet of the muscles runs around and down the back into the lumbodorsal fascia (DVD ref: Functional Lines, 22:40–26:03). The sacral fascia comprises many layers; the BFL passes through the most superficial layers, which may not be separately discernible (DVD ref: Functional Lines, 26:04–29:45). If you stand behind your model with one hand on the sacrum while the model pushes back into your other hand with his lifted elbow, you will feel the sacral fascia tighten to stabilize.

Across the sacrum, we pick up the line with the lower edge of the gluteus maximus where it is attached to the sacrum just above the tailbone (DVD ref: Functional Lines, 29:45–35:18). The BFL includes the lower two inches or so of this muscle. Track this section of the muscle below the gluteal fold (which is not muscular but lies in the superficial fascial layer) down to the next station, the readily discernible lump of connective tissue where the gluteus attaches to the back of the femoral shaft about one-third of the way between the greater trochanter and the knee.

From here, the vastus lateralis can be felt as the muscular part of the lateral aspect of the thigh, diving under the iliotibial tract of the Lateral Line, joining with the rest of the quadriceps at the patella to link through the subpatellar tendon to the tibial tuberosity, clearly palpable at the front-top of the tibial shaft.

The FFL is easier to palpate on oneself. Follow the lower edge of the pectoralis major, which forms the front wall of the armpit, down and in to where it ties into the ribs (DVD ref: Functional Lines, 04:58–8:15). The underlying pectoralis minor could be seen to connect into this line as well (DVD ref: Functional Lines, 08:16–12:24). The next track runs down along the outer edge of the rectus abdominis, which can be felt in most people by actively tightening the rectus and feeling for its edge (DVD ref: Functional Lines, 12:25–15:50). Follow these semilunar lines, a sealed seam of several abdominal layers, down as they narrow down to the outer-upper edge of the pubic symphysis.

The tiny pyramidalis muscle runs obliquely up from the pubic bone and can thus be included as part of this line. The line crosses through the pubis (which may be a bit of a touchy palpation for some clients) but re-emerges in the tendon of the adductor longus on the opposite side (DVD ref: Functional Lines, 15:51–18:58). This tendon is readily palpable and usually visible when one sits cross-legged in a bathing suit or underwear. Follow this tendon into the thigh and you can approach, but usually not reach, the final station where it inserts into the linea aspera on the posterior side of the femur, about halfway down the thigh.

Engaging the lines

Pitching a baseball or bowling at cricket are perfect ways to engage these lines: the wind-up involves a shortening of the BFL and a stretching of the FFL, while the pitch itself reverses that process, shortening the FFL and stretching the BFL (Fig. 8.10) – and the same for the javelin thrower in Figure 8.3. In the final act, the BFL acts as a brake to keep the strong contraction along the FFL and the momentum of the arm from going too far and damaging joints involved in the movement. Baseball pitchers frequently turn up with damage to the rotator cuff tendons, particularly the supraspinatus and infraspinatus, or SLAP tears to the joint labrum. While remedial work on these muscles or their antagonists may be helpful, long-term relief depends on reinforcing the strength and precise timing of the BFL in acting as a whole-body brake to the forward motion of throwing, rather than asking the small muscles of the shoulder joint to bear the entire burden.

Fig. 8.10 The cricket bowler uses the Front Functional Line to add impetus to the power of the arm. See Ch. 10 for further discussion of the Anatomy Trains in movement.

While precise and individual coaching is required to effect this coordination change, the foundation can be laid by teaching the client to engage the line as a whole. Have the client lie prone on the floor or treatment table. Have them lift one arm and the opposite leg at the same time – this will engage the BFL. Most clients, however, will engage the muscles to lift one limb slightly before the other. Laying your hand gently on the humerus and opposite femur in question will allow you to feel with great precision which set of muscles are being engaged first (DVD ref: Functional Lines, 35:20–40:09). Use verbal or manual cues to elicit a coordinated contraction. Once the coordination is achieved, you can build strength by applying equal pressure to both your hands so that the client works against that resistance. Be sure to strengthen both the dominant and non-dominant side for best results.

The FFL can be similarly engaged as a whole with the client supine by using your hands to help them coordinate the engagement of the contralateral girdles (DVD ref: Functional Lines, 43:44–48:17).

Both the Triangle and Reverse Triangle pose of yoga stretch the BFL on the side of the hand reaching for the ground (see Fig. 6.22, p. 145 and DVD ref: Functional Lines, 40:10–43:41). The FFL can be easily stretched from a kneeling position by reaching up and back with a slight rotation toward the reaching arm (DVD ref: Functional Lines, 48:18–50:36 and see Fig. In. 20).

The act of paddling a kayak or canoe engages the stabilizing element of these two lines (Fig. 8.11). The paddling arm connects from the Deep Back Arm Line, pulling from the little-finger side through to the BFL, and thus stabilized to the opposite leg. The upper arm pushes through the Deep Front Arm Line to the thumb, stabilizing via the FFL to the opposite thigh. If the knee is not fixed against the hull of the kayak, the push will be felt passing from foot to foot, almost in imitation of a walking movement.

Fig. 8.11 The kayaker uses the opposite hip to stabilize his paddling – the lowered pulling arm via the BFL, and the lifted pushing arm via the FFL.

The ideal would be that movement and strain pass easily and evenly along these lines (DVD ref: Functional Lines, 50:38–1:04:54). Excess strain or immobility at any track or station along the line could lead to a progressive ‘pile-up’ elsewhere on the line that could lead to problems over time. We have found it useful to accompany a sports enthusiast on an outing, whether it be for a run, a climb, a scull, or a practice, to determine where along these and other lines there may be some ‘silent’ restriction that is creating ‘noisy’ problems elsewhere. The client who is made aware of these lines and the desire for easy flow along them can sometimes do self-assessment when engaged in the sport. In practice, the limitations become especially evident when the client is tired or at the end of a long stint.