Lecture 1: Intro to muscles and upper arm

Lecture 1: Muscular System
Introduction and the Arm
Introduction
Classification
 3 types of body muscles
 Voluntary: muscles that are consciously controlled
 Involuntary: movement of muscles without a conscious input
i.e. peristalsis in the intestines
 Cardiac: also involuntary, a specialised muscle
Muscle attachments
 Attached to bone
 Muscle fibres connect via connective tissue
 Muscle to bone (tendon)
 Muscle to muscle (aponeurosis)
 Origins (starting points) leave no landmarks (proximal)
 Insertions leave landmarks (distal)
 Tubercles and tuberosities
Nomenclature
 Latin derives
 Musculus deltoideus or M Deltoideus (Eng. = deltoid muscle)
 Name classification
 Shape
 Delta = triangular
 Trapezius = table
 Muscle fibre direction
 Rectus abdominus (6 pack) = erect  muscle fibres stand upright
 Internal/external oblique (abdominal muscles)
 Very specific muscle direction
 Location
 Brachialis in the brachium
 Supraspinatus in the supraspinous fossa (scapula)
 Muscle movement
 Pronator teres (forearm pronation)
 Flexor carpi ulnaris and flexor carpi radialis
 Helps to flex at the carpal ulnaris and radialis (wrist) joint
 Number of attachments
 Triceps (2 head origins that come down to a common insertion)
 Biceps (2 head origins)
 Bone(s) attached to
 Coracobrachialis (coracoid  coracoid portion of scapula (coracoid process and arm)
 Sternocleidomastoid (sternum, clavicle and mastoid process)
 The basic concept of how muscles work: muscles pull, they do not push
 Origin = powerhouse of the muscle, anchor and strength come from the origin
 Insertion = where the action takes place
Appendicular muscles

, Upper limb
Shoulder girdle
Trapezius
 Origin
 Medial 1/3 of the superior nuchal line (occipital bone of the cranium)
 Nuchal ligament
 Spinous process (C7-T12)
 Insertion
 Upper fibres on the lateral 1/3 of the clavicle
 Middle fibres on the acromion and scapula spine
 Lower fibres on the tubercle of the scapula spine
 Action
 Shoulder elevation (upper fibres)
 Shoulder retraction (middle fibres)
 Shoulder depression (lower fibres)
 Innervation (nerve supply for a muscle)
 Spinal part of the accessory nerve (cranial nerve)
Levator scapulae
 Origin: the 4 slips on C1-C4 transverse processes
 Insertion: medial border of the scapula
 Action: shoulder elevation
 Innervation: branches of C3-C5  dorsal scapula and cervical
Rhomboid minor and major
 Lies deep to the trapezius
 Origin
 Lower end of the nuchal ligament
 T1-T4 spinous processes
 Insertion
 Medial border of scapula  inferior to scapula spine
 Action
 Hold the scapula against the thoracic wall
 Retraction of the scapula
 Innervation: dorsal scapula (C5)
Serratus anterior
 Origins
 Finger-like processes from the ribs on ribs 1-8
 Insertion: medial side of the scapula costal surface
 Action
 Hold the scapula against the thoracic wall
 Protection of the scapula
 Scapula rotation during abduction
 Innervation: long thoracic nerve (C5-C7)