Pectoral and Pelvic Girdles Flashcards
What are the components of the Pectoral Girdle ?
Scapula and Clavicle
What are the functions of the Pectoral Girdle ?
- Attaches upper limb to the axial skeleton
2. Augments free movement of the limb (incl. by providing muscle attachment)
What are the components of the Pelvic Girdle ?
Hip Bone (Ischium, Ilium, Pubis), sacrum, coccyx
What are the functions of the Pelvic Girdle ?
- Attaches lower limbs to axial skeleton
- Provides almost rigid, complete ring (for weight bearing and childbirth)
- Provides muscle attachment for limb movement
What are the main functions of the clavicle ?
- Increases mobility (holds limbs away from trunk)
2. Transmits forces from upper limb to trunk
Describe the structure of each end of the clavicle + what they articulate with.
Lateral end - flat, articulates with acromion
Medial end - quadrangular, articulates with manubrium of sternum
What is the shape of the medial 1/3 of the clavicle ?
Medial 1/3 is rounded and convex anteriorly
What is the location of the scapula ?
On the postolateral aspect of the thorax
How is the scapula held in position ?
By the clavicle
What is the position of the scapula relative to adjacent ribs ?
Overlying the 2nd (superior angle) -7th ribs (inferior angle)
How many margins does the scapula have ? What are the margins of the scapula called ?
Three
Superior, Medial, Lateral margins
What are the functions of the supra and infraglenoid tubercles ?
Providing attachment for the long heads of the biceps and triceps respectively
What is the function of the glenoid fossa ?
Articulation with the humerus
What is the joint linking pectoral girdle and the body/the only point of attachment of limbs and axial skeleton ?
Sternoclavicular joint
What kind of joint is the sternoclavicular joint ?
Saddle joint
What are the characteristic structures of the sternoclavicular joint ?
Joint capsule
Intra-articular disc (attached to the clavicle, manubrium and the capsule)
Which structures strengthen the capsule of the sternoclavicular joint ?
Ligaments anteriorly and posteriorly + interclavicular and costoclavicular ligaments
What is impingement syndrome ?
Supraspinatus injury or bursitis developping due to arthritis in adjacent joints and repetitive strain injury (affecting acromioclavicular joint)
What kind of joint is the acromioclavicular joint ?
Gliding (=plane) joint
Which structure strengthen the capsule of the acromioclavicular joint ?
Coraco-acromial ligament
Which structures support the acromioclavicular joint as a whole ?
The conoid and trapezoid parts of the coraco-clavicular ligament
Where is the gateway for the pectoral girdle to the upper limb ?
Between the clavicle, superior edge of scapula, and the 1st rib
What goes through the gateway for the pectoral girdle to the upper limb ?
Subclavian vessels and the trunks of the brachial nerve plexus passes to the axilla
What bones make up the hip bone ?
Ilium, Ischium, Pubis
Which joint joins hip bones and sacrum (sacrum ?
Sacro-iliac joint
What structure seperate the three bones of the hip bone ? Is it visible ?
Tri-radiate cartilage (visible radiologically)
Where do the hip bones articulate with each other ?
At the pubic symphysis
What is the level of the the highest point of the iliac crest ?
L4
The anterior superior iliac spine is on the same coronal plane as which other structures ?
Pubic tubercle and pubic crest
What kind of joint is the pubic symphysis ? Where is is present ?
Secondary cartilaginous (=fibrocartilage) joint Between the left and right pubic bodies
Which structures support the pubic symphysis joint ?
Superior and arcuate ligaments
What is the function of the pubic symphysis ?
Limited movement
Shock absorption
What kind of joint is the sacro-iliac joint ? What structures support it ?
Synovial anteriorly and supported by the Anterior sacro-iliac ligament
Fibrous posteriorly and supported by the Posterior sacro-iliac and Interosseous ligaments
What is the function of the sacro-iliac joint ?
Weight Transfer
Very limited movement
What structures support the sacro-iliac joint ? Which other function do they have ?
Sacrospinous and Sacrotuberous ligaments
Preventing the sacrum tilting forwards
Convert the sciatic notches into Greater and Lesser sciatic foramina for the passage of nerves and vessels
What are the main gateways for pelvic girdle ?
Sciatic Nerve and Gluteal Neurovascular Bundle
Obturator Neurovascular Bundle
Femoral Neurovascular Bundle
Internal Pudendal Neurovascular Bundle
Where are the different neurovascular bundles located relative to the body ?
Femoral nerve and vessels ANTERIORLY
Branches of the Obturator nerve and vessels located medially
Sciatic nerve (with posterior femoral cutaneous nerve and inferior gluteal vessels adjacent) located posteriorly
What is the positional relation between sciatic nerve and gluteal region ?
Sciatic nerve emerges into the gluteal region inferior to piriformis muscle and midway between ischial tuberosity and greater trochanter
What is the safe area for intramuscular (intragluteal) injections in the gluteal region ?
Upper, outer quadrant
What are possible movements of the pectoral girdle ?
- Elevation and depression
- Protraction and retraction
- Rotation of scapula (abduction of the arm, so glenoid fossa fasses upward or downward)
What are the main muscles responsible for movement of the pectoral girdle ? How does each muscle aid specifically ?
Serratus Anterior
Trapezius - Upper fibres turn the glenoid fossa upwards (“wing-nut” effect), assisting serratus anterior in full abduction of the upper limb
Levator Scapulae
Rhomboid Major and Minor - Scapular retraction; Stabilises scapula (with serratus anterior)
Pectoralis minor - Stabilises the scapula by holding it down and against the thoracic wall
Subclavius - Anchors clavicle
What is the origin and insertion of the serratus anterior ?
Origin: External surfaces of lateral parts of 1st–8th ribs
Insertion: Medial border of scapula
What is the origin and insertion of the trapezius ?
Origin: Medial third of superior nuchal line, external occipital protuberance, nuchal ligament, spinous processes of and supraspinous ligaments between C7–T12 vertebrae
Insertion: Lateral third of clavicle, acromion and spine of scapula
What is the origin and insertion of the pectoralis minor ?
Origin: 3rd–5th ribs near their costal cartilages
Insertion: Coracoid process of scapula
What is the origin and insertion of the subclavius ?
Origin: Junction of 1st rib and its costal cartilage
Insertion: Inferior surface of middle third of clavicle
What is the origin and insertion of the levator scapulae ?
Origin: Posterior aspect of transverse processes of C1–C4 vertebrae
Insertion: Medial border of scapula, superior to root of spine
What is the origin and insertion of the rhomboid major ?
Origin: Spinous processes of T2–T5 vertebrae
Insertion: Medial border of scapula from level of spine to inferior angle
What is the origin and insertion of the rhomboid minor ?
Origin: Nuchal ligament; spinous processes of C7 and T1 vertebrae
Insertion: Triangular area at medial end of scapular spine
What is the nerve supply of each muscle responsible for movement in the pectoral girdle ?
Trapezius- Spinal accessory nerve
Pectoralis minor- Medial pectoral nerve (C8-T1)
Rhomboid minor and major - Dorsal scapular nerve (C4-5)
Levator scapulae- Dorsal scapular (C4-5) & Anterior rami of C3-4
Serratus anterior- Long thoracic nerve (C5-6-7) (the nerve remains superficial to the muscle)
What is the role of the pelvic girdle in mobility ?
Pelvic girdle immobile BUT provides attachment for muscles involved in hip joint movement and stabilisation
Which structures are moving when one is walking ?
Extension of the hip (when standing from sitting down in general)
Muscles abduct the hip (keep the pelvis level when walking; the neck of the femur is essential for the function of these muscles)
Femur rotates at the hip
What is the position of the serratus anterior relative to nearby structures ?
Wraps around thorax from ribs 1 to 8 to the medial border of the scapula
What is the relation between serratus anterior and the axilla ?
Serratus anterior forms medial wall of axilla
