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)
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)
