Module 05 - Back and Axila Flashcards
What is the sacrum
Large bone located at the terminal part of the vertebral column where it form the posterior aspect of the bony pelvis
Why is the sacrum remarkably thick?
It aids in supporting and transmitting the weight of the body
What is the sacrum composed of?
the 5 fused sacral vertebrae
What does the sacrum articulate with?
The fifth lumbar vertebra (L5) at its base
What is the sacral canal?
continuation of the vertebral canal terminating at the sacral hiatus
What are the sacral foramina?
There are 4, located lateral to the fused sacral bodies on both the anterior and posterior surface. The foramina decreased in size as you go inferior. (Most superior is the largest)
What are the sacral cornua?
there are 2, they are bony processes and are palpated by clinicians as an anatomical landmark when administering injections into the sacral hiatus
What is the promontory?
It the anterior face of the sacrum. It articulates superiorly with the L5 vertebral body. It projects forward and functions to decrease the anteroposterior diameter of the pelvic brim
Why is the sacral promontory of considerable obstetric importance?
Used when measuring the size of the pelvis
What is the coccyx?
It is made of four fused rudimentary coccygeal vertebrae. It articulates with the sacrum superiorly at the sacrococcygeal joint.
Much smaller in size than the sacrum
serves as an attachment site for ligaments and muscles, such as the muscles of the pelvic floor
A small and variable amount of flexion and extension occurs at the sacrococcygeal joint, especially when sitting
What is the sacrococcygeal joint?
Joints that articulate the sacrum and coccyx
What movements is the sacrococcygeal joint capable of?
Small and variable amount of flexion and extension
Neutral in standing position
Flexion (towards the body) when sitting
Moving superior to inferior down the vertebral column, the noticeable trends of the vertebrae are:
Vertebral body size increases
Vertebral Foramen size decreases
Why does the size of the vertebral body increases when moving superior to inferior down the vertebral column?
To support increasing weight
Why does the size of the vertebral foramen decreases when moving superior to inferior down the vertebral column?
To support the spinal cord diameter decreasing as spinal nerves exit to their respective regions of the body
What are accessory ligaments of the vertebral column and what is their function?
Strong fibrous bands of tissue that stabilize the vertebral column and protect the intervertebral discs
Involved in movements of flexion and extension of the back
What are the 3 major accessory ligaments of the vertebral column?
Ligamentum flavum
Anterior Longitudinal ligament
Posterior longitudinal ligament
What is lumbar stenosis?
Narrowing of the vertebral canal in the lumbar region
May be caused by calcification of the ligamentum flavum or bone outgrowth
It compresses the spinal cord which can cause numbness and weakness in the lower limb
What are the 5 extrinsic muscles of the back?
Latissimus dorsi Trapezium Rhomboid minor Levator scapulae Rhomboid major
Describe the location and anatomy of the latissimus dorsi
Broad, triangular-shaped extrinsic muscle of the back. It covers the lumbar region and inferior portion of the thoracic cage.
It has multiple points of origin and, as such, has varying muscle fiber directions
it inserts at the intertubercular sulcus (bicipital groove) of the humerus
What is one of the largest point of origin of the latissimus dorsi (for this course)?
Thoracolumbar fascia
broad fascial sheath
What is the function of the latissimus dorsi?
Extends, adducts and medially rotates the arm
What is the function of the erector spinae muscles?
Extending (straightening) the vertebral column
What are the 3 muscles of the erector spinae?
Iliocostalis (most lateral)
Longissimus (middle)
Spinalis (most medial)
Which erector spinae muscle is the longest and widest?
iliocostalis
What are the 3 divisions of the iliocostalis
Cervicis
thoracis
lumborum
Where would you feel the pain from a iliocostalis lumborum strain?
sacroiliac region (lumbar spine to top of buttocks)
Where would you feel the pain from a iliocostalis thoracis strain?
Along the medial border of the scapula and posterior thorax.
Referred pain can affect the anterior thorax if the strain muscle irritates underlying intercostal nerves
What is the axilla?
aka armpit
Pyramidal shaped space between the upper thorax and arm.
Passage way for major nerves and blood vessels to enter the upper limb
What are the borders of the axilla? (6)
Anterior wall: Pectoralis major Posterior wall: Subscapularis, latissimus dorsi, and teres major Medial wall: Serratus anterior Lateral wall: Intertubercular sulcus of the humerus Apex: Base of neck Base: Skin
Which lymph nodes are located in the axilla?
Axillary lymph nodes
What is the brachial plexus?
Network of nerves that supplies motor and sensory innervation to the upper limb
Begins in the neck, passes through the axilla, and runs through the entire upper limbs
What are the 5 parts of the brachial plexus?
Roots Trunks Divisions Cords Branches
What are the roots of the brachial plexus?
Formed from the ventral rami of spinal nerves C5-T1
5 spinal nerves exits through the intervertebral foramen
What are the trunks of the brachial plexus?
5 spinal nerves convert into 3 trunks
Superior, middle and inferior
What are the divisions of the brachial plexus?
3 trunks EACH divide into 6 divisions
3 anterior and 3 posterior
What are the cords of the brachial plexus
Once the anterior and posterior division have entered the axilla they combine together to form 3 cords
name by their position relative to axillary artery
What are the five nerve branches of the brachial plexus?
The 3 cords give rise to 5 major terminal nerve branches
- musculocutaneous nerve
- Axillary nerve
- Median nerve
- Radial nerve
- Ulnar nerve
What is the general function of the musculocutaneous nerve?
Motor innervation of the anterior compartment (flexion) of the arm
What is the general function of the axillary nerve?
Motor innervation to the deltoid (abduction of arm), and teres minor (lateral rotation of arm)
What is the general function of the median nerve?
Motor innervation of the anterior compartment (flexion) of the forearm, as well as some intrinsic muscles of the hand
What is the general function of the Radial nerve?
Motor innervation of the posterior compartment extension of the arm and forearm
What is the general function of the ulnar nerve?
Motor innervation of the anterior compartment (flexion0 of the forearm as well as some intrinsic muscles of the hand
Which branch(es) of the brachial plexus ONLY innervate muscles of the posterior compartment of the arm and forearm?
Radial nerve
What artery is the preferred pulse point at the wrist?
radial artery
What is the artery supply “pathway” of the upper limb, start at the aorta?
Aorta subclavian artery axillary artery brachial artery (splits in 2) Radial & Ulnar arteries
What are the 7 veins of the upper limb?
Radial vein Ulnar Vein Cephalic Vein Basilic Vein Median Cubital Vein Brachial Vein Axillary Vein
Which vein does the axillary vein drains into?
subclavian vein
What is the function of the Radial vein?
Drains blood from deep structure of the palm and lateral aspect of the forearm
What is the function of the Ulnar vein?
Drain blood from deep structures of the palm and median aspect of the forearm
What is the function of the Basilic vein?
Long vein that carries blood from the brachial vein and superficial structures of the hand and travels medially to drain into axillary vein
What is the function of the Cephalic vein?
Long vein that drains blood from superficial structures of the hand. It ascends the arm laterally to drain into the axillary vein
What is the function of the brachial vein?
Receives blood from radial and ulnar vein. It also has small tributaries that carry blood form the biceps and triceps brachii. It drain directly into the basilic vein
What is the function of the median cubital vein?
Located within the cubital fossa, this vein connects the basilic and cephalic veins.
It is often the site of venipuncture for drawing blood
Which upper limb vein is often the site of venipuncture for drawing blood?
median cubital vein
What is the function of the Axillary vein?
Large vein is formed by the brachial, basilic, and cephalic veins. Tributaries of this vein drain the thorac and axilla. It becomes the subclavian vein