17 (91)

SKELETAL MUSCULAR SYSTEM / LOWER LIMB

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CN: (1) Color each hamstring muscle in ihe deep vigw before going on to the superficial. Then color the diagrams of flexion and extension. (2} Color gray the outline of the muscies m the drawings at upper right.

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The hamstring muscies are edually effective at both extension of the nip joint and flexion ot the knee joint. Unlike the hip extensor gluteus maximus, the hamstnngs are active durmg normal walking. In re!axed standing, both gluteus maximus and the namstrings are mactive. In knee flexion, the ham-strings act in concert with sartorius, gracilis. and gastrocnemius (Plates 63 and 66). Long tendons of the hamstnngs can be palpated just above the partially flexed knee on either side of the midline.

Reduced hamstring stretch ("tight namstrings") limits hip tlexion with the knee extended; ilexion of the knee permits ncreased hip flexion. Try this on yourself Tight hamstnngs, by their ischial origin, puli the postenor peivis down lengthenmg the erector spmae muscies and fiattemng the lumbar lor-dosis. potentially contributing to lirritaticn of lumbar movement and back pam. Tight hamstnngs cften cause postenor thigh pam on straight leg raise testing (subiect is supine. lower limbs horizontal; one heel is lifted, progressivety flexing the hip joint with knee extendedL This pain frcm muscle stretch

62

See 61, 63

Tighl hamstnngs Umil )lexion of hip when knee joint is extended.

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POSTERIOR VIEW

Gracihs

Sartonus

Tignt hamstfings (at right) tilt pelvis oackwards, tlaitening lordotic curve of lower back

Gluteus

■naiimus

Gastrocnerr.ius

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SUPERFICIAL

I(f/ Head ot fibula

Acductor Linea magnus aspera

Femur

Shorl head

Long head

Powertut ex',ensors oł the hip |Q:nts

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