Hip anatomy and function

Hip anatomy and function - Lab 5
Each lab group needs a copy of each of the following:

calculator (1)
tape measure (1)
skin pencil (1)
reflex hammer
textbooks (1 copy of each)

Anatomy text of your choice
Hertling, D., & Kessler, R. M. (1996). Management of common musculoskeletal disorders: Physical therapy principles and methods. (3rd ed.). Philadelphia: J.B. Lippincott.
Kendall, F.P., McCreary, E.K., & Provance, P.G. (1993). Muscles: testing and function (4th ed.). Baltimore: Williams & Wilkins.
Smith, L.K., Weiss, E.L. & Lehmkuhl, L.D. (1996). Brunnstrom's clinical kinesiology (5th ed.). Philadelphia: F.A. Davis. Pages pp. 94-103 concern Golgi tendon organs and muscle spindle, the latter of which are involved in stretch reflexes, the topic of one of the lab problems.
Pages 131-135 provide a general discussion of functional relationships among muscles, the ways in which muscles function together in various tasks. Pages 288-298 discuss more specifically some functional relationships among the muscles that cross the hip joint. Several of the lab problems relate directly to this section of the text.

Locate on yourself and on a partner the palpable structures that your text (Smith,Weiss, & Lehmkuhl, 1996, pp. 267-268) lists for the hip.

iliac crests
anterior superior iliac spines (ASIS)
posterior superior iliac spines (PSIS)
greater trochanter of the femur
ischial tuberosities
pubic symphysis (superior aspect)
rami of pubis

Use the laboratory skeleton, your anatomy atlas, Kendall's (1993) text, and the detailed instructions on muscle palpation in Smith, Weiss, and Lehmkuhl (1996, pp. 279-288) to locate points and lines of application for the muscles listed. Predict their actions at the hip and compare your predictions with your texts' descriptions. When a muscle is composed of many fibers, each with its own line of application, different parts of the muscle can produce different joint motions (Smith, Weiss, & Lehmkuhl, p.289).

superior portion of gluteus maximus (those fibers whose lines of application are superior to the hip's A-P axis)
inferior portion of gluteus maximus (those fibers whose lines of application are inferior to the hip's A-P axis)
anterior portion of gluteus medius (those fibers whose lines of application are anterior to hip's lateral and longitudinal axes)
posterior portion of gluteus medius (those fibers whose lines of application are posterior to hip's lateral and longitudinal axes)
tensor fascia lata
sartorius

Make your predictions by analyzing the relationship between the muscle's line(s) of application with each of the hip's three axes. Use figures that depict the hip in each of the three planes in which it moves.
Different parts of a muscle can produce different moments or actions around a joint. In addition, some muscles produce different moments or actions in different parts of a joint's range of motion. Your text explains such an "inversion of action" (Smith, Weiss, & Lehmkuhl, 1996, p. 289) in the adductor group of muscles, which flex or extend the hip in different parts of the ROM. Use the laboratory skeletons to verify this fact.
Electromyographic (EMG) studies have demonstrated that the adductors produce internal rotation around the hip's longitudinal axis (Kendall, McCreary, & Provance, 1993, p.230; Smith, Weiss, & Lehmkuhl, 1996, p. 295). Examine the classroom skeletons to understand how kinesiologists have resolved this mechanical puzzle.
Examine the figure in your text (Smith, Weiss, & Lehmkuhl, 1996, Fig. 8-18B, p.297) that illustrate unilateral stance. Perform a vector analysis in the frontal plane, focusing on the hip joint on the stance extremity.
Because the lower extremity is fixed on the floor, unilateral stance is a closed-chain activity, and the moving segment includes the "HAT" (head-arms-trunk) and all the mass that is superincumbent to the hip joint on the stance side. Draw vectors on the moving segment to represent (1) gravity's force and (2) the force of the hip abductors.
Use a lab partner's body as your model to estimate forces and moment arms. Use your vector diagram to prove that gravity produces hip adduction on the stance limb.
To level the pelvis, as illustrated in figure 8-18B (p.297), hip abductors must produce a moment that balances gravity's adductor moment. Although several muscles contribute to the abductor moment, you may simplify the problem by drawing a single line of application, and estimating a single moment arm for the entire group of hip abductors.
Use the equation for rotation equilibrium to calculate the force that the hip abductors must generate to level the pelvis.
Repeat your analysis for figure 8-18C (p. 297). By leaning to the side of the stance limb, the person changes gravity's moment arm with respect to the hip joint on which he or she stands. Calculate the muscle force that the hip abductors must produce to level the pelvis in figure 8-18C, and show that it is less than the quantity you calculated for figure 8-18B.
As a member of your lab group lies supine and flexes the left hip, palpate his or her abdominal muscles. The abdominal muscle activity that you detect stabilizes the pelvis as the hip flexors act on the femur.
Draw a sagittal plane diagram that illustrates hip flexors' and abdominals' force as vectors with points of application on the pelvis. (Do this even though the pelvis is not the moving bone.) Use the diagram to explain the abdominals' role in stabilizing the pelvis as one performs open chain hip flexion while supine.
As a member of your lab group lies on the right side and abducts the left (uppermost) hip against the force of gravity, palpate muscles in the trunk to decide if they act to stabilize the pelvis.
Muscles contain specialized sensory receptors, muscle spindles, that detect increases in muscle length. Stretch reflexes, which are easily elicited in certain muscles (Hertling & Kessler, 1996, Table 5-7, p. 90), illustrate the muscle spindles' sensory function. Using your reflex hammer, test your lab partners' biceps reflex (p. 568; Fig. 17-22A, p. 542) and quadriceps (knee jerk) reflex (p. 656).
Review the four components of the stretch reflex "arc" (Smith, Weiss, & Lehmkuhl, 1996, Fig. 3-13, p.100), including the receptor, the afferent and efferent neurons, and the "effector." An abnormal stretch reflex does not identify the specific component or structure that is damaged or dysfunctional. However, finding an abnormal reflex causes the therapist to suspect a problem in a specific neurological segment. Use Hertling and Kessler's text to complete these statements:

An abnormal biceps reflex points to a problem in the _ segment.
An abnormal quadriceps reflex suggests a problem in the _ segment.

Extras / above and beyond the call of duty / not found in any course objective (at least not this semester)

Examine the hamstrings' moment arms with respect to the hip's antero-posterior (AP) axis. How do the lengths of these moment arms change in different regions of the joint's range of motion for abduction and adduction? What effect does this have on the hamstrings' ability to abduct or adduct the hip.
Stand on your left foot and rotate the right side of the pelvis forward in the transverse plane. (We typically term this movement "right forward pelvic rotation.") First, name the closed chain movement that occurs at the left hip. Next, identify on a diagram the muscle forces that produce the movement.

Diagrams of the hip in three planes:

sagittal
frontal
transverse

Last updated 9-12-01 Dave Thompson PT
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