OCC313 Muscles of the Upper and Lower Limbs.pdf

OCC313 Biomedical Science Topic 2: Muscles of the Upper and Lower Limbs Marieb and Hoehn 9th Edition Chapters 9&10. Dr.Safaa Elkholi  Learning Objectives 1. Revise the structure and function of skeletal muscles of the upper and lower limbs, with particular focus on types of muscle cont...

OCC313 Biomedical Science Topic 2: Muscles of the Upper and Lower Limbs Marieb and Hoehn 9th Edition Chapters 9&10. Dr.Safaa Elkholi  Learning Objectives 1. Revise the structure and function of skeletal muscles of the upper and lower limbs, with particular focus on types of muscle contraction 2. Describe how muscles interact with each other and the different functional roles they may play to achieve desired movement 3. Revise the divisions of the muscular system and the terminology used to describe their anatomical location 4. Discuss the origin of the nerve supply to the muscles of the upper limb 5. Describe in detail the name, origin, insertion, action and nerve supply of the muscles of the upper and lower limbs Skeletal Muscle Structures Muscle tissue (muscle cells or fibers) Connective tissues Nerves Blood vessels (remember the excellent material from last year in Chapter 9 of Marieb and Hoehn 9th ed.) Functions of Skeletal Muscles 1. Produce skeletal movement 2. Maintain body position 3. Support soft tissues 4. Guard body openings 5. Maintain body temperature  Contraction of skeletal muscle Two main categories of contractions –Isotonic Muscle length changes to move a load –Concentric and Eccentric –Isometric Muscle length does not change despite muscle reaching its peak tension-producing capacity Isotonic Contraction Skeletal muscle changes length: – resulting in motion If muscle tension > resistance: – muscle shortens (concentric contraction) If muscle tension < resistance: – muscle lengthens (eccentric contraction) Isometric Contraction Skeletal muscle develops tension, but is prevented from changing length Note: Iso = same, metric = measure 9 Muscle Interactions Muscles work in groups to maximize efficiency Individual muscles are able to play different roles depending on desired movement Marked complexity of movement beyond simple “flexion and extension”  Skeletal Muscles: Functional Groups 1. Prime movers – Provide the major force for producing a specific movement 2. Antagonists – Oppose or reverse a particular movement – Help regulate action of prime mover by contracting slightly to provide some resistance Prevent ‘overshooting’ the mark or help slow down or stop the movement Skeletal Muscles: Functional Groups 3. Synergists – Add force to a movement – Reduce undesirable or unnecessary movement 4. Fixators – Synergists that immobilize a bone or muscle’s origin Divisions of the Muscular System 1. Axial muscles: – position head and spinal column – move rib cage – 60% of skeletal muscles 2. Appendicular muscles: – support pectoral and pelvic girdles – support limbs – 40% of skeletal muscles  Origins and insertions Muscles are usually described in terms of their ‘origin’ and ‘insertion’ Remembering muscles cross joints and attach to bone. During contraction, a muscle usually causes a movable bone to move toward a less movable (or immovable) bone. That is, the insertion moves towards the muscle’s origin. A muscle’s origin is typically more proximal to its insertion. Upper limb musculature Brachial plexus and the upper limb Large network of complicated interlacing nerves- a ‘web’ Situated in the neck and the axilla Gives rise to virtually all nerves that supply the upper limb Consists of ventral rami of C5-C8 and T1 with some contribution from C4 and T2 Brachial plexus Ends in axilla, where the three resulting cords give rise to the main nerves of the upper limb Axillary nerve Musculocutaneous nerve Median nerve Ulnar nerve Radial nerve The Brachial Plexus Axillary nerve Nerve roots C5 C6 Radial C7 nerve C8 Ulnar nerve T1 Musculocutaneous nerve Median nerve Muscles Crossing the Shoulder Joint Movements at the shoulder include flexion, extension, abduction, adduction, internal and external rotation, circumduction Nine muscles cross the shoulder joint to insert on and move the humerus Muscles Crossing the Shoulder Joint Some originate off the scapula; others originate off the axial skeleton – Three are prime movers of the arm Pectoralis major Latissimus dorsi Deltoid – Actions include flexion, extension, adduction, abduction, and rotation of humerus  Prime movers of arm Pectoralis major – Origin- sternal end of clavicle, sternum, cartilage of ribs 1-7 – Insertion- intertubercular sulcus – Action : Prime mover of arm flexion Medial rotation of arm Arm adduction – Ns. Lat. and Med. Pectoral nerve 23 Prime movers of arm Deltoid – Origin- lateral end clavicle, acromion and spine of scapula – Insertion- deltoid tuberosity of humerus – Action: Prime mover of arm abduction when all fibres contracting Arm flexion and medial rotation if anterior fibres only Extension and lateral arm rotation if posterior fibres only – Innervation from Axillary Nerve 25 Prime movers of arm Latissimus dorsi – Origin- lower 6 thoracic vertebrae, all lumbar vertebrae, lower 3-4 ribs and iliac crest – Insertion :Intertubercular sulcus of humerus – Action :Prime mover of arm extension, adduction and medial rotation – NS.: thoracodorsal nerve Muscles crossing the shoulder joint Deltoid Deltoid (cut) Latissimus dorsi Pectoralis major Muscles Crossing the Shoulder Joint Four muscles are rotator cuff muscles – Supraspinatus – Infraspinatus – Teres minor – Subscapularis Reinforce the capsule of the shoulder Act as synergists and fixators Two additional muscles are synergists: coracobrachialis and teres major  Rotator cuff muscles Supraspinatus – Origin- supraspinous fossa of scapula – Insertion- greater tubercle of humerus – Action: Initiates arm abduction, stabilises shoulder – NS. The suprascapular nerve Infraspinatus – Origin- infraspinous fossa of scapula – Insertion- greater tubercle of humerus – Action: Lateral rotation of humerus, stabilises humeral head in glenoid cavity – NS. The suprascapular nerve 30  Rotator cuff muscles Teres minor – Origin- lateral border scapula – Insertion- greater tubercle of humerus – Action : Lateral rotation of arm, stabilises humeral head – NS. axillary nerve Subscapularis – Origin- subscapular fossa of scapula – Insertion- lesser tubercle of humerus (passes in front of shoulder joint) – Action : Medial rotation of humerus, stabilises humeral head – NS. lower subscapular nerve 32 Rotator cuff muscles Supraspinatus Infraspinatus Teres minor Subscapularis Teres major Coracobrachialis  Synergists Teres major – Origin- posterior scapula at inferior angle – Insertion- lesser tubercle of humerus - Action: Extends, medially rotates and adducts arm Synergist of lat. dorsi – NS. subscapular nerve Coracobrachialis – Origin- coracoid process scapula – Insertion- medial surface shaft of humerus – Action: Flexion and adduction of humerus Synergist of pec. Major – N.S Musculocutaneous nerve 35  Supraspinatus* Spine of scapula Deltoid (cut) Greater tubercle of humerus Infraspinatus* Teres minor* Teres major Triceps brachii: Lateral head Long head Latissimus dorsi Humerus Olecranon process of ulna Anconeus Posterior * Rotator cuff muscles Muscles Crossing the Elbow Joint Anterior flexor muscles –Brachialis and biceps brachii— chief forearm flexors –Brachioradialis—synergist and stabilizer  Anterior flexors Brachialis –Origin- distal humerus –Insertion- coronoid process of ulna –Action :Prime mover of forearm flexion –Innervation from Musculocutaneous nerve  Anterior flexors Biceps brachii – Origin- short head= coracoid process long head= supraglenoid tubercle of scapula (through intertubercular sulcus) – Insertion- common tendon into radial tuberosity of radius – Action: Prime mover elbow flexion, supinator of forearm – Innervation from Musculocutaneous nerve Anterior flexors Brachioradialis – Origin- lateral supracondylar ridge, distal end humerus – Insertion- base of radial styloid process – Action: Synergist in forearm flexion, stabilises elbow – Innervation by Radial nerve  Clavicle Deltoid Sternum Pectoralis major Coracobrachialis Biceps brachii Brachialis Brachioradialis Anterior  Pronators Anterior compartment muscles, but not flexors Pronator teres :. Origin : medial epicondyle of humerus and coronoid process of the ulna Insertion: lateral radius mid shaft. Sits between brachioradialis laterally and flexor carpi radialis medially. Pronator quadratus- originates on the distal ulnar shaft to insert on the distal radius. Muscles Crossing the Elbow Joint Posterior extensor muscles –Triceps brachii—prime mover of forearm extension –Anconeus—weak synergist Posterior extensors Triceps brachii – Origin long head= infraglenoid tubercle lateral and medial heads= posterior shaft of humerus – Insertion- olecranon of ulna – Action : Prime mover of elbow extension Antagonist of forearm flexors – Innervation by Radial nerve Posterior extensors Anconeus – Origin- lateral epicondyle of humerus – Insertion- lateral olecranon of ulna – Action: Stabilises ulna during pronation Synergist of triceps brachii in extension – Innervation by Radial nerve Supinator – Assists biceps brachii to supinate forearm – Antagonist of pronator muscles Supraspinatus* Spine of scapula Deltoid (cut) Greater tubercle of humerus Infraspinatus* Teres minor* Teres major Triceps brachii: Lateral head Long head Latissimus dorsi Humerus Olecranon process of ulna Anconeus Posterior * Rotator cuff muscles  Lateral head Triceps Long brachii head Medial Posterior head compartment of arm (extends Humerus elbow); innervation: Extensors Flexors radial nerve Others Brachialis Short head Biceps brachii Long head (a) (a) Muscles of the arm Anterior compartment of arm (flexes elbow); innervation: musculocutaneous nerve Forearm muscles moving the wrist Many forearm muscles arise from the humerus but have minimal action on the elbow. At the wrist, flexion and extension are major movements, also abduction and adduction Anterior flexors, and posterior extensors  Anterior compartment flexors Flexor carpi radialis – Origin- medial epicondyle humerus – Insertion- base of second and third metacarpals – Action: Prime mover of wrist flexion Abduction of hand Weak synergist elbow flexion – Innervation by Median nerve  Anterior compartment flexors Flexor carpi ulnaris – Origin- medial epicondyle of humerus, olecranon and posterior surface ulna – Insertion- pisiform and hamate and base of fifth metacarpal – Action: Prime mover of wrist flexion Adduction of hand (with extensor carpi ulnaris) – Innervation by Ulnar nerve Posterior compartment extensors Extensor carpi radialis longus and brevis – Origins- lateral epicondyle of humerus – Insertions- base of second (longus) and third (brevis) metacarpals – Action: Both muscles extend and abduct the wrist and work synergistically together – Innervation by Radial nerve Posterior compartment extensors Extensor carpi ulnaris – Origin- lateral epicondyle of humerus and posterior ulna – Insertion- base of fifth metacarpal – Action: Prime mover of wrist extension and adduction N.S : posterior interosseous nerve Flexor carpi ulnaris Flexor carpi radialis Pronator teres  Extensor carpi ulnaris Extensor carpi radialis brevis Extensor carpi radialis longus Forearm muscles moving the hand Flexor digitorum superficialis – Origin- medial epicondyle humerus, coronoid process of ulna, radial shaft – Insertion- middle phalanges of fingers 2,3,4,5 – Action: Flexion at wrist and middle phalanges (2-5) Important finger flexor – Innervated by Median nerve Forearm muscles moving the hand Flexor digitorum profundus – Origin- coronoid process, anteromedial ulna, interosseous membrane – Insertion- distal phalanges fingers 2,3,4,5 – Action: Flexes distal interphalangeal joints – Innervation by Ulnar nerve (medial half) and Radial nerve (lateral half) Forearm muscles moving the hand Flexor pollicis longus – Origin- anterior surface of radius and interosseous membrane – Insertion- distal phalanx of thumb – Action: Flexes distal phalanx of thumb – Innervation by anterior interosseous nerve (AIN), a branch of the median nerve Flexor digitorum superficialis Flexor digitorum Flexor profundus pollicis longus Forearm muscles moving the hand Extensor digitorum – Origin- lateral epicondyle of humerus – Insertion- distal phalanges of fingers 2,3,4,5 Separate portion of this muscle called Extensor digiti minimi, extends little finger – Action: Prime mover of finger extension Extends wrist Can abduct fingers – Innervation by Radial nerve Forearm muscles moving the hand Extensor pollicis longus and brevis – Origins- dorsal shaft of radius and ulna, interosseous membrane – Insertions- base of proximal (brevis) and distal (longus) phalanx of thumb – Prime mover thumb extension – N.S: posterior interosseous nerve which is a continuation of a deep branch of radial nerve  Forearm muscles moving the hand Abductor pollicis longus – Origin- posterior radius and ulna, interosseous membrane – Insertion- base of first metacarpal and trapezium – Abducts and extends thumb (carpometacarpal jt) Extensor indicis – Small extensor muscle arising from posterior ulna, joining with tendon of extensor digitorum – Extends index finger  Superficial Deep Extensor indicis Extensor Extensor pollicis digitorum brevis Extensor digiti minimi Extensor pollicis longus Abductor pollicis longus Intrinsic hand muscles Control precise movements of fingers All are in the palm (none on dorsum) Thenar eminence (ball of thumb) Hypothenar eminence (ball of little finger) Midpalm  Thenar muscles Abductor pollicis brevis – Abducts thumb at carpometacarpal joint Adductor pollicis – Adducts thumb – Helps oppose thumb Flexor pollicis brevis – Flexes thumb at carpometacarpal and metacarpophalangeal joints Opponens pollicis – Opposition of thumb  Adductor pollicis Opponens digiti minimi Flexor pollicis brevis Flexor digiti minimi brevis Abductor pollicis brevis Abductor digiti minimi Opponens pollicis Abductor pollicis longus tendon Hypothenar muscles Abductor digiti minimi – Abducts little finger (MCP joint) Flexor digiti minimi brevis – Flexes little finger (MCP joint) Opponens digiti minimi – Helps oppose little finger to thumb Midpalm muscles Lumbricals – Flex fingers at metacarpophalangeal joints – Extend fingers at interphalangeal joints Palmar interossei – Four muscles between metacarpals – Adduct fingers Dorsal interossei – Four muscles between metacarpals deep to palmar interossei – Abduct fingers Palmar Dorsal interossei interossei Lower limb musculature Muscles Crossing Hip and Knee Joints Most anterior muscles flex the femur (thigh) at the hip and extend the leg at the knee (foreswing of walking) Most posterior muscles extend the femur (thigh) at the hip and flex the leg (backswing of walking) Medial muscles all adduct the thigh All three groups are enclosed by the fascia lata Movements of the Thigh Include flexion, extension, abduction, adduction, circumduction, and rotation Thigh flexors pass in front of the hip joint – Iliopsoas (iliacus and psoas major): prime mover of flexion – Tensor fasciae latae – Rectus femoris Assisted by medial adductors and sartorius  12th rib 12th thoracic vertebra Quadratus lumborum Psoas minor Iliac crest Psoas major Iliopsoas Iliacus 5th lumbar vertebra Anterior superior iliac spine Tensor fasciae latae Pectineus Sartorius Adductor longus Gracilis Quadriceps femoris Adductor magnus Rectus femoris Vastus lateralis Vastus medialis Tendon of quadriceps femoris Patella Patellar ligament Movements of the Thigh Thigh extensors Hamstring muscles (prime movers of extension) – Biceps femoris – Semitendinosus – Semimembranosus Gluteus maximus (prime mover during forceful extension) Gluteus medius Gluteus maximus Adductor magnus Gracilis Iliotibial tract Long head Biceps Short head femoris Hamstrings Semitendinosus Semimembranosus Movements of the Thigh Adductors (also medially rotate thigh) – Adductor magnus – Adductor longus – Adductor brevis – Pectineus – Gracilis Pectineus (cut) Adductor brevis Adductor magnus Adductor longus Femur O = origin I = insertion Figure 10.19b Movements of the Thigh Abductors Gluteus maximus (also laterally rotates thigh) Gluteus medius (also medially rotates thigh) Gluteus minimus (also medially rotates thigh) – Piriformis (also laterally rotates thigh) – Obturator externus (also laterally rotates thigh) – Obturator internus (also laterally rotates thigh) – Gemellus (also laterally rotates thigh) – Quadratus femoris (also laterally rotates thigh)  Gluteus medius (cut) Gluteus minimus Superior gemellus Piriformis Obturator Obturator internus externus Inferior Quadratus gemellus femoris Gluteus maximus (cut) Muscles of the Thigh that Move the Knee Joint Quadriceps femoris—sole extensor of the knee Hamstring muscles—flex the knee, and are antagonists to the quadriceps femoris  12th rib 12th thoracic vertebra Quadratus lumborum Psoas minor Iliac crest Psoas major Iliopsoas Iliacus 5th lumbar vertebra Anterior superior iliac spine Tensor fasciae latae Pectineus Sartorius Adductor longus Gracilis Quadriceps femoris Adductor magnus Rectus femoris Vastus lateralis Vastus medialis Tendon of quadriceps femoris Patella Patellar ligament Gluteus medius Gluteus maximus Adductor magnus Gracilis Iliotibial tract Long head Biceps Short head femoris Hamstrings Semitendinosus Semimembranosus Fascia of the Leg A deep fascia of the leg is continuous with the fascia lata This fascia segregates the leg into three compartments: anterior, lateral, and posterior Distally, the fascia thickens and forms the flexor, extensor, and fibular retinaculae Muscles of the Leg: Movements Various leg muscles produce the following movements –Ankle—dorsiflexion and plantar flexion –Intertarsal joints—inversion and eversion of the foot –Toes—flexion and extension Muscles that Move the Foot Dorsiflexion and inversion of the foot – Tibialis anterior Plantar flexion – Gastrocnemius Triceps surae – Soleus – Plantaris Fibularis longus Gastrocnemius Tibia Tibialis anterior Extensor digitorum longus Soleus Extensor hallucis longus Fibularis tertius Superior and inferior extensor retinacula Extensor hallucis brevis Extensor digitorum brevis  Plantaris Soleus Gastrocnemius Medial head Lateral head Tendon of gastrocnemius Calcaneal tendon Superficial view of the posterior leg.  Adductors Hamstrings Vastus lateralis Femur Posterior compartment of Vastus thigh (flexes leg and extends intermedius thigh); innervation: tibial nerve (portion of sciatic nerve) Rectus femoris (a) Vastus medialis Posterior compartment muscles Anterior compartment muscle Medial compartment Medial compartment (adducts muscles of thigh thigh); innervation: obturator Anterior compartment (extends leg); and lateral nerve compartment innervated by femoral nerve muscles of leg Muscles of the thigh  Posterior compartment muscles Anterior Triceps surae compartment muscle Fibula Medial Fibularis compartment muscles muscles of thigh and lateral compartment muscles of leg Posterior compartment of leg (plantar flexes foot, (b) flexes toes); innervated by tibial nerve Tibialis anterior Tibia Lateral compartment of leg (plantar flexes and everts foot); innervation: superficial fibular nerve Anterior compartment of leg (dorsiflexes foot, extends toes); Muscles of the leg innervated by deep fibular nerve