ANAT1521-2111_Muscular System_2024 T2.pdf

Introductory Anatomy ANAT1521-2111 Muscular System Dr. Amaneh Mohammadiroushandeh Anatomy Department / School of Biomedical Sciences / Medicine and Health UNSW SYDNEY [email protected] Amaneh Mohammadiroushandeh/ Ph.D Learning objectives...

Introductory Anatomy ANAT1521-2111 Muscular System Dr. Amaneh Mohammadiroushandeh Anatomy Department / School of Biomedical Sciences / Medicine and Health UNSW SYDNEY [email protected] Amaneh Mohammadiroushandeh/ Ph.D Learning objectives Understand the organization and structure of muscles and how this relates to function Identify muscles of the head and neck and understand their functions based on their attachments Identify muscles of the upper limb and shoulder girdle and understand their functions based on their attachments Identify muscles of the trunk and understand their functions based on their attachments. Identify muscles of the lower limb and pelvic girdle and understand their functions based on their attachments.  Skeletal Muscle Organisation Bound within deep fascia. Arranged into functional groups separated by connective tissue ( septae) Muscle fibres are organised into bundles or fascicles. Muscles fascicle are aligned in different patterns in different muscles. Intermuscular septae Interosseous memberane Deep fascia Superficial fascia Skin  Muscle fascicle arrangement Parallel Pennate Muscle power is a function of the cross-section area (i.e number of fibres/fascicles). Parallel patterns can generate a long length of contraction at the sacrifice of power. Pennate and convergent patterns can pack in many more fibres for more power, but at the sacrifice of length of contraction. Other arrangements allow the generation of specific movements such as pursing the lips. Circular pattern Orbicularis oris Parallel pattern Pennate pattern Staplike Fusiform Unipennate Bipennate Multipennate Sartorius Biceps brachii Extensor digit. long. Rectus femoris Deltoid Convergent pattern Pectoralis major Muscle attachments and actions Muscles are connected to tendons, which anchor them to bones. All muscles have at least two attachments: the origin and the insertion Most muscles cross at least one joint, with the origin and insertion on opposing bones. In the limbs, the origin of a muscle is proximal and the insertion is distal Muscles can only pull; they never push During contraction, the muscle insertion moves toward the origin  Role in movement An agonist (prime mover) - the principle muscle(s) generating the movement. An antagonist - the opposing muscle(s) which slow/control the prime movement. A synergist - muscle(s) that assist the agonist in generating its movement. A fixator - stabilizes/prevents unwanted movement at a joint A movement can be categorized according to how the muscle changes: Isometric Muscle tone changes during the movement Isotonic Muscle length doesn’t change during the movement Muscle tone doesn’t change during the movement Muscle length changes during the movement  Typical of statically resisting gravity Concentric Eccentric Muscle shortens during Muscle lengthens during the movement the movement Typical of the agonist generating Typical of the antagonist working to the prime movement slow the prime movement 6 Learning objectives Understand the organization and structure of muscles and how this relates to function Identify muscles of the head and neck and understand their functions based on their attachments Identify muscles of the upper limb and shoulder girdle and understand their functions based on their attachments Identify muscles of the trunk and understand their functions based on their attachments. Identify muscles of the lower limb and pelvic girdle and understand their functions based on their attachments.  Muscles of facial expression Epicranial aponeurosis Origin: Bones of skull Occipitofrontalis Insertion: Skin of face Obicularis oculi  1- Occipitofrontalis (Raises eyebrow) 2. Orbicularis oculi (Closes eyelids) 3. Orbicularis oris (closes and compress lips) Occipitofrontalis 4. Buccinator (compress the cheeks against Obicularis oris the teeth) Buccinator 8 Occipitofrontalis Orbicularis Oculi Orbicularis Oris Buccinator Muscles of mastication Temporalis Permit movement of the mandible, cheeks and lips ( 4 Muscles, you need to learn two of them) 1.Temporalis Origin: Temporal fossa Insertion: Mandible Action: elevates and retracts the mandible 2. Masseter Origin: zygomatic arch Insertion: angle of mandible Action: elevates and protrudes the mandible Masseter 9 Muscles of the neck region Permit movements of the head and neck Need to know: 1.Sternocleidomastoid Origin: Sternal head – manubrium Clavicular head – medial clavicle Insertion: Mastoid process Action: Unilateral contraction rotates head to contralateral side; Bilateral contraction flexes head Sternocleidomastoid Learning objectives Understand the organization and structure of muscles and how this relates to function Identify muscles of the head and neck and understand their functions based on their attachments Identify muscles of the upper limb and shoulder girdle and understand their functions based on their attachments Identify muscles of the trunk and understand their functions based on their attachments. Identify muscles of the lower limb and pelvic girdle and understand their functions based on their attachments. 11  Muscles of the upper limb 1- Muscles of the anterior arm Biceps brachii Muscles of the shoulder girdle Brachialis Arm 2. Muscles of the posterior arm 1. Muscles connecting upper limb to thoracic wall Triceps brachii Pectoralis major 2. Muscles connecting upper limb to vertebral column Trapezius Latissimus dorsi 3. Muscles connecting upper limb to scapula 1. Muscles of the anterior forearm Forearm Deltoid Teres major 2. Muscles of the posterior forearm Rotator cuff group Intrinsic muscles of the hand Hand 12  Muscles connecting upper limb to thoracic wall Pectoralis major Origin: medial 2/3 clavicle; body of sternum; costal cartilages 2-6 Insertion: lateral lip of intertubercular sulcus of humerus Pectoralis major Action: Shoulder flexion (prime mover) Shoulder adduction (prime mover) Medial rotation  Muscles connecting upper limb to vertebral column Trapezius Origin: Occipital bone(external occipital protuberance) C7-T12 spinous processes Insertion: Lateral Clavicle Scapular acromion & spine Action: Shoulder elevation, scapular retraction, depression and upward rotation of the scapula; neck extension Muscles connecting upper limb to vertebral column Posterior Anterior Latissimus dorsi Origin: T7-L5 spinous processes ribs 8-12; thoracolumbar fascia Insertion: Middle of intertubercular sulcus of humerus Action: Shoulder extension (prime mover) Adduction (prime mover) Latissimus dorsi Medial rotation Muscles connecting upper limb to scapula Deltoid Origin: Lateral clavicle; Scapular (acromion & spine) Insertion: Deltoid tuberosity of humerus Deltoid Action: shoulder abduction (prime mover) Anterior part - shoulder flexion & medial rotation(prime mover) Posterior part - shoulder extension & lateral rotation (prime mover)  Posterior Muscles connecting upper limb to scapula Teres major Origin: inferior angle of scapula, lateral border of scapula Insertion: medial lip of intertubercular sulcus of humerus Action: shoulder extension, adduction, & medial rotation Muscles connecting upper limb to scapula Lateral Rotator cuff group Four muscles with a common function to stabilize the glenohumeral joint 1. Supraspinatus Origin: Supraspinous fossa Insertion: Superior aspect of greater tubercle Action: Shoulder abduction (first 15° only) 2. Infraspinatus Origin: Infraspinous fossa Insertion: Posterior aspect of greater tubercle Action: Lateral rotation of arm Anterior Posterior 3. Teres minor Origin: Lateral border of scapula Insertion: Posterior aspect of greater tubercle Supraspinatus Action: Lateral rotation of arm Infraspinatus Subscapularis Teres minor 4. Subscapularis Origin: Subscapular fossa Insertion: lesser tubercle Action: Medial rotation of arm Muscles of the anterior compartment of the arm Anterior Long head of biceps brachii Short head of biceps brachii Biceps brachii Origin: Short head - coracoid process of scapula; Long head - supraglenoid tubercle Insertion: Radial tuberosity (radius) Action: Flexion of elbow & shoulder joint; supination of the forearm (crosses two joints!) Muscles of the anterior compartment of the arm Anterior Brachialis Origin: shaft of humerus Insertion: Ulnar tuberosity (ulnar) Brachialis Action: Flexion of elbow joint (prime mover)  Posterior Muscles of the posterior compartment of the arm Triceps brachii Origin: Long head - infraglenoid tubercle of scapula Lateral head - lateral shaft of humerus Lateral head of triceps brachii Medial head - posterior shaft of humerus Long head of triceps brachii Medial head of triceps brachii Insertion: Olecranon process of ulna Action: All heads: extension of elbow joint long head only: extension of arm at shoulder joint (crosses shoulder joint) Muscles of the anterior compartment of the forearm Do not need to learn the individual muscle names! Common origin: Medial epicondyle of humerus Insertion: Bones of the forearm and hand Action: Pronation of the forearm; flexion of the hand at wrist joint; flexion of the digits Carpal tunnel The carpal tunnel is formed by the flexor retinaculum bridging across the carpal bones of the wrist. The carpal tunnel is the passageway for tendons of the digit flexor muscles entering to the hand. Muscles of the posterior compartment of the forearm Do not need to learn the individual muscle names! Common origin: Lateral epicondyle of humerus Insertion: Bones of the forearm and hand Action: Supination, Extension of the hand at wrist joint; extension of the digits Intrinsic Muscles of the Hand Do not need to learn the individual muscle names! Common function is for fine motor movements of the digits. Flexion and extension, abduction and adduction, of metacarpo-phalangeal (MCP) joints Flexion and extension of inter-phalangeal joints Learning objectives Understand the organization and structure of muscles and how this relates to function Identify muscles of the head and neck and understand their functions based on their attachments Identify muscles of the upper limb and shoulder girdle and understand their functions based on their attachments Identify muscles of the trunk and understand their functions based on their attachments. Identify muscles of the lower limb and pelvic girdle and understand their functions based on their attachments. 25 Muscles of the back Intrinsic/deep group: Erector spinae group Superficial/Extrinsic group: Superficial layer Action: (Bilateral) Extension of the trunk (Unilateral) Ipsilateral lateral flexion of the trunk Trapezius Latissimus dorsi Muscles of abdominal wall Rectus sheath Linea alba (‘white line’) External obliques Action: Transversus abdominis (Bilateral) Flexion of the trunk; Compression of the abdominal wall Tendinous intersection (Unilateral) Ipsilateral lateral flexion and contralateral rotation of the trunk Internal Oblique Rectus abdominis Internal obliques External Oblique Action: (Bilateral) Flexion of the trunk; Compression of the abdominal wall (Unilateral) Ipsilateral lateral flexion, and ipsilateral rotation of the trunk Transversus abdominis Inguinal ligament Action: Compression of the abdominal wall Rectus abdominis Action: Flexion of the trunk; Compression of the abdominal wall Horizontal cross-section Common function to compress the abdominal wall Learning objectives Understand the organization and structure of muscles and how this relates to function Identify muscles of the head and neck and understand their functions based on their attachments Identify muscles of the upper limb and shoulder girdle and understand their functions based on their attachments Identify muscles of the trunk and understand their functions based on their attachments. Identify muscles of the pelvic girdle and lower limb and understand their functions based on their attachments. 28 Muscles of the pelvic girdle Muscles of the lower limb 1. Muscles of the anterior thigh Sartorius Quadriceps femoris group 1. Gluteal muscles Rectus femoris Vastus lateralis Rotator group Vastus medialis Gluteus minimus Vastus intermedius 2. Muscle of the medial thigh Gluteus medius Adductor group Thigh Gluteus maximus 3. Muscles of the posterior thigh Biceps femoris Semitendinosus 2. Hip flexor muscles Semimembranosus Iliacus Psoas major 1- Muscles of the anterior leg 2- Muscles of the lateral leg 3- Muscles of the posterior leg Leg Gastrocnemius Soleus Deep group - Intrinsic muscles of the foot Foot  Gluteal muscles Superficial group: Gluteus Gluteus maximus maximus Origin: Gluteal surface of the ilium, sacrum and coccyx Insertion: Greater trochanter and gluteal tuberosity of femur; Iliotibial tract Actions: Extension of thigh at hip joint (Prime mover) Abduction & lateral rotation of thigh at hip joint Gluteus minimus Gluteus medius (Prime movers for hip abduction and medial rotation) Deep group Rotator group Hip flexor muscles Psoas major Psoas major Origin: T12-L5 vertebrae Insertion (as iliopsoas m.): Lesser trochanter of femur Iliacus Actions: Flexion of thigh at hip joint (prime mover); Flexion of the trunk Iliacus Origin: Iliac fossa Insertion (as iliopsoas m.): Lesser trochanter of femur Actions: Flexion of thigh at hip joint (prime mover) Muscles of the anterior thigh Sartorius Origin: Anterior superior iliac spine Insertion: Medial and proximal aspect of tibia Actions: Flexion & lateral rotation of thigh at hip joint; Flexion of leg at Sartorius knee joint Cross both joints Muscles of the anterior thigh Quadriceps femoris: Rectus femoris Vastus lateralis Vastus medialis Vastus intermedius Origin: Anterior inferior iliac spine (Rectus femoris) Insertion: Quadriceps femoris tendon (then via patellar Ligament to tibial tuberosity) Actions: Common Action: Extension of leg at knee joint (prime mover) Action of Rectus femoris only - Flexion of leg at knee joint and thigh at hip joint (crosses both knee and hip joints)  Muscles of the medial thigh Do not need to learn the individual muscle names! Adductor group Common origin: Pubis and ischium of the pelvis Common insertion: Medial aspect of the femur Action: Adduction of the thigh at the hip joint (prime movers) Muscles of the posterior thigh (Hamstring Muscles) Superficial posterior Biceps femoris Origin: Long head - Ischial tuberosity Short head - posterior femur Insertion: fibula Actions: Extension of hip joint Flexion of leg at knee joint (prime mover) (crosses two joints) Short head Tendon Link to image Link to image  Superficial posterior Muscles of the posterior thigh Semitendinosus Origin: Ischial tuberosity Insertion: Tibia Semitendinosus Semitendinosus Actions: Extension of hip joint Flexion of leg at knee joint (prime mover) (crosses two joints) Link to image  Superficial posterior Deep posterior Muscles of the posterior thigh Semimembranosus (Deep and most medial) Origin: Ischial tuberosity Insertion: Tibia Semimembranosus Actions: Extension of hip joint Semimembranosus Flexion of leg at knee joint (prime mover) (crosses two joints)  Medial head of Muscles of the posterior leg Gastrocnemius Lateral head of Gastrocnemius Superficial layer: Gastrocnemius Origin: Medial and lateral condyles of the femur Soleus Insertion: Calcaneus via Achilles tendon Action: Plantarflexion of foot; Flexion of leg at knee joint Gastrocnemius (crosses two joints) Soleus (Deep) Origin: Tibia and fibula Insertion: Calcaneus via Achilles tendon Action: Plantarflexion of foot  Deep layer: Link to image Extrinsic muscles of foot Link to image Common action: Plantarflexion of foot and flexion of digits 38  Muscles of the anterior leg Common action: Dorsiflexion and extension of digits Muscles of the lateral leg Common action: Foot eversion Do not need to learn the individual muscle names!  Intrinsic Muscles of the Foot Extensor muscle group (dorsum of foot) Common action: Extension of digits Flexor muscle group (Sole of foot or plantar aspect) Common action: Flexion of digits Do not need to learn the individual muscle names! Thank you