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Trapezius - upper, middle, and lower division - CORRECT-ANSWERSOrigins: large, important, diamond shaped muscle; its origin is on the occiput, nuchal ligament, and spinous process of the cervical vertebrae and thoracic vertebrae Insertions : the lateral third of the clavicle and acromion (upper fibers), scapular spine (middle fibers), a tubercle at the medial end of the scapular spine (lower fibers) Actions of the Muscles:simultaneous contraction of all the fibers adducts the scapula upper fibers: elevation and upward rotation of the scapula lower fibers: depression and upward rotation of the scapula Levator Scapulae - CORRECT-ANSWERSOrigins: originates from the transverse processes of C1-C Insertions : inserts on the superior angle of the scapula Actions of the Muscles : elevates the scapula and rotates it downwards Tibialis anterior & posterior - CORRECT-ANSWERStibialis anterior - originates from the lateral condyle and superolateral shaft of tibia, passes under the extensor retinaculum, and inserts on the medial cuneiform this muscle is the strongest dorsiflexor posterior - Extensor hallucis longus - CORRECT-ANSWERSextensor hallicus longus - arises from the central medial fibula and interosseous membrane, passes under the extensor retinaculum, and inserts dorsally on distal phalanx I. actions - dorsiflexion of big toe and foot; also supination Extensor digitorum longus - CORRECT-ANSWERSoriginates from the lateral tibial condyle, most of the anterior fibular shaft, and interosseous membrane. its tendon passes under the extensor retinaculum, splits into
four parts, and inserts on toes II-V. each of the four tendons further splits into two slips attaching to the sides of the middle phalanx, and a central slip attaching to the base of the distal phalanx actions - dorsiflexion of toes II-V, foot, and ankle; it mainly acts on the proximal phalanx and is one of the muscles responsible for the "clawing" action of the toes Peroneus tertius, longus & brevis - CORRECT-ANSWERSperoneus tertius - insignificant muscle, absent in some individuals. it arises from the anteroinferior fibula and inserts on metatarsal V actions - dorsiflexion and eversion of the foot peroneus brevis - arises from the inferolateral fibular shaft, where it is covered by peroneus longus; its tendon passes behind the lateral malleolus under the peroneal retinaculum, superior to the peroneal tubercle and inserts on the lateral tubercle of metatarsal V actions- pronator; assists in plantar flexion and abduction of foot peroneus longus - arises from the head and superolateral shaft of fibula; its tendon follows a complicated path behind the lateral malleols, under the peroneal retinaculum, inferior to the peroneal tubercle of calcaneus, along the groove of the cuboid, and finally inserts inferiorly on the base of the medial cuneiform and base of metatarsal I. actions - pronator and lowers medial edge; plantar flexes ankle Flexor hallucis longus - CORRECT-ANSWERSarises from the posteroinferior fibula and interosseous membrane, runs posterior to the medial malleous, along a groove on the posterior talus, behind sustentaculum tali, along the medial plantar surface of the foot, and inserts on distal phalanx I. actions - plantar flexion of big toe and ankle, inversion, support of medial arch; assists in plantar flexion and adduction of foot Flexor digitorum longus - CORRECT-ANSWERSoriginates from the posteromedial tibial shaft, runs posterior to the medial malleolus and sustentaculum tali, along the plantar surface of the foot, and inserts on distal phalanges II-V. actions - plantar flexion of toes II-V and ankle, inversion of foot, support of arches. This is the most powerful flexor of toes II-V. It also assists in plantar flexion, supination, and adduction of the foot, the latter counteracted by quadratus plantae Rhomboid Major and Minor - CORRECT-ANSWERSOrigins: originate from the spinous process of C7 and T1-T Insertions: insert on the medial border of the scapula
Insertions: on the medial surface of the humeral shaft, near the middle Actions of the Muscles: flexes and adducts the arm shoulder muscle Latissimus dorsi - CORRECT-ANSWERSOrigins: sacral and iliac crests, throracolumbar fascia, spinous processes of T7-T12, and posterior surfaces of the four lower ribs Insertions: The tendon wraps around the medial side of the humerus, makes a twist, and inserts on the bicipital groove Actions of the Muscles: extension, adduction, and medial rotation of the arm meaning "widest back muscle" Teres Major - CORRECT-ANSWERSOrigins: originates from the posterior surface of the inferior angle of the scapula Insertions: on the medial aspect of the bicipital groove, next to the latissimus dorsi Actions of the Muscles: extension, adduction, and medial rotation of the arm (less powerful than the latissimus dorsi Rotator cuff muscles - supraspinatus, teres minor, infraspinatus, subscapularis - CORRECT-ANSWERSOrigins: these tendons surround and reinforce the shoulder-joint capsule on three side Supraspinatus - prevents the humerus from being dislocated and displaced upward and from gliding forward and backward Teres Minor and Infraspinatus - prevent the humerus from being dislocated forward Subscapularis - prevents the head of the humerus from gliding backwards Actions of the Muscles: providing mobility to the joint Triceps brachii (shoulder) - CORRECT-ANSWERSActions of the Muscles: adduction at the arms Biceps brachii (shoulder) - CORRECT-ANSWERSActions of the Muscles: flexion; the long and short heads are also involved in abduction and adduction
Triceps brachii (elbow) - CORRECT-ANSWERSOrigin: the long head comes from a tubercle below the glenoid cavity of the scapula, the lateral head is from the lateral posterosuperior shaft of the humerus, and the medial head is from the posteroinferior humerus Insertion: Action: major elbow extensor; extension of the arm due to its attachment to the scapula Biceps brachii (elbow) - CORRECT-ANSWERSOrigin: 2 origins. #1 long head - arises from a tubercle above the glenoid cavity of the scapula, travels through the shoulder joint, between the greater and lesser tubercles, and along the bicipital groove before merging with the body #2 short head - starts as a tendon at the coracoid process on the lateral edge of the scapula and becomes a fleshy body which joins with the muscle fibers of the long head about halfway down the humerus Insertion: the two heads continue downward and form one tendon which passes anterior to the elbow joint and inserts at the bicipital tuberosity of the radius Action: the muscle is the primary elbow flexor and also supinates the radius at the elbow Anconeus - CORRECT-ANSWERSOrigin/Insertion: small muscles running from the lateral epicondyle of the humerus to the superior ulna Action: extends the elbow; plays a small role as an abductor during pronation of the ulna Brachioradialis - CORRECT-ANSWERSOrigin: originates from a lateral ridge on the distal humerus Inserts: via a long tendon on the base of the radial styloid process Action: flexes the elbow. In pronation or supination, this muscle brings the forearm into a middle position Brachialis - CORRECT-ANSWERSOrigin: arises from the anterior surface of the distal humerus Inserts: on the coronoid process Action: major flexor of the elbow
Rectus Capitis Lateralis Origin/Insertion: runs from the occipital bone (which lies anterior to the rectus capitis anterior) to the anterior atlas Action: flexion of the head relative to the atlas (bilateral contraction) and sidebending and rotation (unilateral, on the side of the contraction) Rectus capitis posterior major & posterior minor Obliques capitis superior & inferior - CORRECT-ANSWERSrectus capitus posterior major - originates from the spinous process of c2 and inserts just lateral to the minor rectus capitus posterior minor - runs from the posterior arch of c1 to the inferior occipital ridge 2 rectus capitus muscles - produce right rotation obliques capitis superior - originates from the transverse process of c and inserts on the occiput lateral to rectus capitis posterior major, just posterior to the mastoid process of the temporal bone. has the most lateral insertion and produces left rotation by contracting on the right obliques capitus inferior - runs from the spinous process of c2 to the transverse process of c Action: these three muscles help produce extension at c1/c2 joint when they contract bilaterally Intertransversarii (intertransverse muscles) - CORRECT-ANSWERSsmall muscles of the back found between contiguous transverse processes of the cervical, lumbar, and some thoracic, vertebrae Rotatores longus & brevis - CORRECT-ANSWERSThe rotatores pass toward the lamina of the vertebra above origin - inferior transverse process brevis insertion - lower border and lateral surface of the superior lamina longus insertion - base of spinous process Deepest muscles of the transversospinalis Multifidus - CORRECT-ANSWERSpass to the spinous processes of the vertebrae that are located two to four levels above innermost and deepest layer of muscle in the back, allowing one to have spinal extension, flexion, and rotation
Semispinalis thoracis, cervicis & capitis - CORRECT-ANSWERSSemispinalis muscles pass to the spinous processes of the vertebrae that are located four to six layers above, covering the other layers Spinalis capitis/ semispinalis capitis (can be considered together) Origin: They originate respectively from the spinous process of C7-T1 and the transverse processes of C4-T4 and insert on the occiput Actions: if they contract bilaterally, while the cervical spine is fixed, they extend the head. If they contract unilaterally, with the spine fixed, they can contribute to sidebending or rotation If they contract bilaterally with the head fixed, they tend to straighten out the cervical spine ** The back muscles form a deep muscle layer aka spinal muscles. They have a short lever arm, not much power needed to do certain activities. They are very active muscles able to work with fatiguing for long stretches of time. Iliocostalis lumborum, thoracis & cervicis - CORRECT-ANSWERSIliocostalis lumborum - originates from the illiac crest via the lumbar fascia and inserts into the lower ribs Iliocostalis thoracis - runs from the lower six to the upper six Iliocostalis cervicis - runs from the upper six ribs to the transverse processes of the lower cervicals **The main action of all these muscles is extension of the spine; By contracting unilaterally, they also contribute to sidebending (iliocostalis lumborum) and rotation Longissimus Cervicis & capitis - CORRECT-ANSWERSLongissimus capitis contributes to extension of the head (bilateral contraction) or sidebending of the head (unilateral contraction) Spinalis thoracis & cervicis - CORRECT-ANSWERSSpinalis thoracis - runs from the spinous processes of T1 through T10 to the spinous processes of T11 through T Action - extends the spine in the thoracic region Splenius cervicis & capitis - CORRECT-ANSWERSOrigin - (capitis) originates from the nuchal ligament and the spinous processes of C7 through T3-T4. It inserts on the mastoid process and adjacent occipital bone Splenius cervicis runs from the spinous process of T5-T7 to the transverse processes of C1-C
Actions: when the skull is fixed, SCM elevates the sternum and clavicle, assisting in inspiration when the thoracic cage is fixed, unilateral contraction of SCM causes ipsilateral sidebending and contralateral rotation of the head, as well as extension bilateral contraction results in extension of the head, accentuating cervical lordosis Rectus abdominis - CORRECT-ANSWERSis located anteriorly inside a "rectus sheath" formed by the aponeuroses of the three preceding muscles it runs from the crest and symphysis of the pubis to the xiphoid process and cartilages of ribs 5- the rectus adheres to the anterior layer of its sheath at three tendinous intersections, which are visible as transverse grooves when the muscle contracts actions: by moving the sternum toward the pelvis, it is the most direct flexor of the trunk; it can also flex the trunk by tilting the pelvis backward External oblique - CORRECT-ANSWERSOrigin: is attached above to the outer surfaces of ribs 5-12 (where its fibers intertwine with those of the serratus anterior) and to the ilioinguinal ligament. In front and below, it forms a broad aponeurosis ending and contributing to the linea alba and inguinal ligament Actions: unilateral contraction of the external oblique side-bending and contralateral rotation of the spine and ribcage Bilateral contraction causes flexion of the trunk; the oblique muscle works synergetically in the rotation of the trunk Internal oblique - CORRECT-ANSWERSInternal oblique lies between the transversus and external oblique It is attached below to the inguinal ligament and the iliac crest; posteriorly to the lumbodorsal fasica; above, to the lower four ribs; and anteriorly to a very broad aponeurosis Actions: unilateral contraction of the internal oblique results in sidebending or ipsilateral rotation of the spine and ribcage. If the pelvis is fixed, it acts on the ribs, and vice versa
When the pelvis is fixed, bilateral contraction causes compression of the abdomen and assists in flexion of the trunk. When the vertebrae and the pelvis are fixed, it lowers the ribs and moves them backward. Diaphragm - CORRECT-ANSWERSBig, flat muscle with "radiating" fibers, located inside the thoracic cage. It extends like a dome between the thoracic and abdominal cavities Diaphragm inserts on its own central tendon, which is composed of strong interlacing fibrous tissue External intercostals - CORRECT-ANSWERSrun downward and foreward to the rib occupy the spaces between adjacent ribs Internal intercostals - CORRECT-ANSWERSthe fibers of the intercostals run downward and backward to the upper border of the rib action: the intercostals form a muscular sheet, which joins the ribs to each other, making the thoracic cage a contiguous entity. occupy the spaces between adjacent ribs Levatores costarm longis & brevis - CORRECT-ANSWERSrun from the transverse process of a thoracic vertebra to the tubercle of a rib located one or two levels below action: assists in rotation of the spine or elevation of the ribs, depending on which end is fixed Serratus posterior superior & inferior - CORRECT-ANSWERSsuperior: runs from the spinous process of C7 to T3 and inserts on the first five ribs action: elevates the ribs and aids in inspiration interior: runs from the spinous process of T12 to L2 and inserts on the last four ribs action: depresses these ribs and aids in expiration Transversus abdominis - CORRECT-ANSWERSdeepest of the four abdominal layers it attaches below to the inguinal ligament and the iliac crest; posteriorly to the five lumbar vertebrae; above to the inner surfaces of the last seven ribs contraction of these circular fibers reduces the diameter of the abdomen; when the vertebrae are fixed it pulls in the belly
Tensor fasciae latae - CORRECT-ANSWERSoriginates on the anterior superior iliac spine flexes, medially rotates, and abducts the femur small part in knee extension or lateral rotation of the flexed knee Pectineus - CORRECT-ANSWERSorigin - runs from the lateral pubis to a line connecting the lesser trochanter to the linea aspera of the femur actions - flexes and adducts the thigh when the hip contracts Adductor magnus, brevis & longus - CORRECT-ANSWERSadductor magnus- largest and strongest of the adductor group actions - adduction of the hip adductor brevis - runs from the medial pubis to the middle part of the linea aspera adductor longus - originates medially on the pubis and runs anterior to adductor brevis almost completely covering it Piriformis - CORRECT-ANSWERSorigin: on the anterior sacrum and passes under the greater sciatic notch and inserts of the greater trochanter actions: if the sacrum is fixed, piriformis laterally rotates, abducts, and flexes the femur; if the femur is fixed, it contributes to extension of the pelvis or to medial rotation of the pelvis Obturator externus & internus - CORRECT-ANSWERSobturator externus - arises from the external surface of the obturator membrane, passes posterior to the femoral neck, and inserts on a fossa on the medial surface of the greater trochanter actions - if the pelvis is fixed, it laterally rotates, flexes, and abducts the femur; if the femur is fixed, it functions in flexion of the pelvis and also medially rotates and flexes the pelvis obturator internus - arises from the obturator membrane and adjacent portions of the ischium and ilium Its fibers pass posteriorly through the lesser sciatic notch, make a sharp bend around the body of the ischium, and insert of the medial aspect of the greater trochanter actions: if the pelvis is fixed, this muscle laterally rotates, flexes, and abducts the thigh
if the femur is fixed, the muscles act in extension and in medial rotation or medial flexion Gemellus superior & inferior - CORRECT-ANSWERSare small muscles located above and below the distal borders of obturator internus, at the level of the lesser sciatic notch They reinforce the actions of obturator internus Quadratus femoris - CORRECT-ANSWERSorigin: runs from the lateral ischium, posterior to the obturator foramen, and horizontally to the posterior aspect of the greater trochanter actions: if the pelvis is fixed, quadratus femoris laterally rotates the thigh; if the femur is fixed, it contributes to extension of the pelvis or to medial rotation of the pelvis quadriceps femoris is - CORRECT-ANSWERSa massive muscle having 4 bodies (rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius) converges into a single quadriceps tendon Rectus femoris - CORRECT-ANSWERSarises from the anterior inferior iliac spine and part of the ilium near the acetabulum, and passes superficial to the three vasti to insert on the common tendon. it crosses the hip, as well as the knee Vastus medialis, intermedius & lateralis; Actions of the quadriceps and Actions of the Medialis and Lateralis - CORRECT-ANSWERSintermedius - the deepest of the muscle bodies, originates from the upper two thirds of the anterior femoral shaft its fibers follow the axis of the femur is covered by... the vastus medialis and vastus lateralis actions: quadriceps extends the knee. It is the strongest muscle in the body actions: vastus medialis and lateralis rotate the tibia in their respective directions; when the knee is extended, the two muscles act to stabilize the knee against lateral displacement, complement the actions of the ligament Biceps femoris - CORRECT-ANSWERSis located laterally. The two heads of this muscle merge inferiorly and insert via a common tendon to the head of the fibula. This tendon is bifurcated by the lateral collateral ligament of the knee. acts in lateral rotation
actions of the triceps surae - CORRECT-ANSWERSthe three muscles pull the calcaneus into plantar flexion under the talus with a tendency to inversion... and indirectly pull the talus into plantar flexion. the second action is actually more important than the first because it gives the joint more mobility
