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By the end of this section, you will be able to:
  • Identify the muscles of the pectoral girdle and upper limbs
  • Identify the movement and function of the pectoral girdle and upper limbs

Muscles of the shoulder and upper limb can be divided into four groups: muscles that stabilize and position the pectoral girdle, muscles that move the arm, muscles that move the forearm, and muscles that move the wrists, hands, and fingers. The pectoral girdle    , or shoulder girdle, consists of the lateral ends of the clavicle and scapula, along with the proximal end of the humerus, and the muscles covering these three bones to stabilize the shoulder joint. The girdle creates a base from which the head of the humerus, in its ball-and-socket joint with the glenoid fossa of the scapula, can move the arm in multiple directions.

Muscles that position the pectoral girdle

Muscles that position the pectoral girdle are located either on the anterior thorax or on the posterior thorax ( [link] and [link] ). The anterior muscles include the subclavius    , pectoralis minor    , and serratus anterior    . The posterior muscles include the trapezius    , rhomboid major    , and rhomboid minor    . When the rhomboids are contracted, your scapula moves medially, which can pull the shoulder and upper limb posteriorly.

Muscles that position the pectoral girdle

The left panel shows the anterior lateral view of the pectoral girdle muscle, and the right panel shows the posterior view of the pectoral girdle muscle.
The muscles that stabilize the pectoral girdle make it a steady base on which other muscles can move the arm. Note that the pectoralis major and deltoid, which move the humerus, are cut here to show the deeper positioning muscles.
Muscles that Position the Pectoral Girdle
Position in the thorax Movement Target Target motion direction Prime mover Origin Insertion
Anterior thorax Stabilizes clavicle during movement by depressing it Clavicle Depression Subclavius First rib Inferior surface of clavicle
Anterior thorax Rotates shoulder anteriorly (throwing motion); assists with inhalation Scapula; ribs Scapula: depresses; ribs: elevates Pectoralis minor Anterior surfaces of certain ribs (2–4 or 3–5) Coracoid process of scapula
Anterior thorax Moves arm from side of body to front of body; assists with inhalation Scapula; ribs Scapula: protracts; ribs: elevates Serratus anterior Muscle slips from certain ribs (1–8 or 1–9) Anterior surface of vertebral border of scapula
Posterior thorax Elevates shoulders (shrugging); pulls shoulder blades together; tilts head backwards Scapula; cervical spine Scapula: rotests inferiorly, retracts, elevates, and depresses; spine: extends Trapezius Skull; vertebral column Acromion and spine of scapula; clavicle
Posterior thorax Stabilizes scapula during pectoral girdle movement Scapula Retracts; rotates inferiorly Rhomboid major Thoracic vertebrae (T2–T5) Medial border of scapula
Posterior thorax Stabilizes scapula during pectoral girdle movement Scapula Retracts; rotates inferiorly Rhomboid minor Cervical and thoracic vertebrae (C7 and T1) Medial border of scapula

Muscles that move the humerus

Similar to the muscles that position the pectoral girdle, muscles that cross the shoulder joint and move the humerus bone of the arm include both axial and scapular muscles ( [link] and [link] ). The two axial muscles are the pectoralis major and the latissimus dorsi. The pectoralis major    is thick and fan-shaped, covering much of the superior portion of the anterior thorax. The broad, triangular latissimus dorsi    is located on the inferior part of the back, where it inserts into a thick connective tissue shealth called an aponeurosis.

Questions & Answers

If a molecule can only pass through a membrane with the assistance of a membrane protein, but the direction of its travel is controlled only by its concentration, the process is called?
osmosis
chozen
A 52 year old woman turned her head quickly, during a tennis game and suddenly felt a sharp pain in her neck along her upper limb. Physical examination and medical imaging revealed a herniated degenerated IV disc in the cervical region of her vertebral column.
Isaac
a. What probably caused the IV disc herniation? b. What cause IV disc degeneration? c. What are the result of disc degeneration?
Isaac
Describe the neural control of erection and ejaculation.
Nana Reply
A 52 year old woman turned her head quickly, during a tennis game and suddenly felt a sharp pain in her neck along her upper limb. Physical examination and medical imaging revealed a herniated degenerated IV disc in the cervical region of her vertebral column. a)What probably caused the IV di
Isaac
a) What probably caused the IV disc herniation? b) What cause IV disc degeneration? c) What are the result of disc degeneration?
Isaac
iv disc herniation compress the nerve cause numbness tingling sensation even paralysis in severe cases...
Khawaja
explain more
DANIELLA Reply
yes
Ramzan
function of skeleton
Josiah Reply
- for movement - blood production by the bone marrow
Daniel
production of calsium and phosphorus
Juma
Shortly after childbirth, a woman consulted her physician about a tender swelling in her perineal region. 8. What fossa related the perineal swelling? 9. Describe what vessel may cause the collection of blood in the fossa after childbirth?
Isaac
what is heart
Subhajit Reply
it is the tissue..which pump blood to the all parts of body
GRAY
the heart is a conical , hollow, muscular organ which works continuously through out the life of a person ,it is about the size of a clenched fist and weighs about 300 grams and also the heart is in the chest just behind the breast bone and between the two lungs
Mary
a hollow muscular organ that pumps blood through the circulatory system by regular contractions
Johnny
is a muscular organ that pumps blood lungs and other body tissues through vessels
Nolosha
Shortly after childbirth, a woman consulted her physician about a tender swelling in her perineal region. 8. What fossa related the perineal swelling? 9. Describe what vessel may cause the collection of blood in the fossa after childbirth?
Isaac
Shortly after childbirth, a woman consulted her physician about a tender swelling in her perineal region. 8. What fossa related the perineal swelling? 9. Describe what vessel may cause the collection of blood in the fossa after childbirth?
Isaac Reply
inguinal fossa femoral vein?
Jeen
if you dont the answer by now you should seek another line of work. as a professor it is my duty to let you know about your lacking.
Arif
branches of brachial plexus
Arooj Reply
musculocutaneous, median, ulnar, axillary, and radial nerves.
Shakerah
Shortly after childbirth, a woman consulted her physician about a tender swelling in her perineal region. a.What fossa related the perineal swelling? b.Describe what vessel may cause the collection of blood in the fossa after childbirth?
Isaac
What is great Auricular nerve?
ZUBAIR Reply
it originates from the cervical plexus that provides sensory innervation to the skin.
Daniel
why it is called Auricular nerve
Amber
is any payment is needed to use this app
Suprith Reply
is it a question?
Samenjo
doubt about this app
Suprith
which lines divide the body into nine quadrant
Julius Reply
nine regions of abdomen can b marked using two horizontal & two vertical lines...the vertical lines are the mid clavicular lines taken from the mid point of each clavicle. the upper horizontal lines is the subcostal line taken from the inferior parts of the lowest costal cartilage...
Khawaja
to get a better understanding for the function
Rashana Reply
anatomy and physiology work closely together
Rashana
anatomy to you about the structure of the while physiology is the the study of the body function
Rashana
what is the difference between negative and positive feedback
Rashana
The key difference bewteen positive and negative feedback is their response to change. Positive feedback amplifies change while negative reduces change.
ladychen
negative feed back produces a response that brings back to normal while positive feed back produces a response that stimulates
Julius
examples of the body structure
Naki Reply
body's structure
Naki
how is it possible
Adum Reply
what is homeostasis please
Ayobami Reply
Homeostasis is the ability of the body to maintain a constant internal environment, regulation factors such as the body's temperature, pH, water balance, blood pressure.
Jude
that is true
Maria
A young man was playing in a hockey game when he was knocked down, he was not wearing a helmet and hit his head on the ground. He momently stunned and said he saw stars. The man’s vision was blurred for approximately 20 seconds. He left to his bench and showed no other sign of injury except tha
Isaac
that he complained of lingering head ached.
Isaac
1.Do you think the person would have a fracture skull? Explain your answer 2What will the lingering headache indicate 3. If you detected clear fluid dipping from the person nose. What do you suspect might be the source of the fluids?
Isaac
if he broke his skull he will have not survied
Maria
1. if there were no other signs of external injury such as blood or bruising around area of impact or areas of the face, then he more than likely didn't fracture his skull 2. lingering headache could indicate a concussion 3. clear fluid dripping from nose would suggest a cerebrospinal fluid leak
Amber
(and fracturing of the skull does not indicate the person would not survive, of course dependant upon the severity of the impact & internal damage caused)
Amber
what is homeostasis
Rashana
function of microvilli
Suprith
it gives the small intestine a wider surface area which helps absorption to take place
Enada
please what is a lymph
Ayobami Reply
lymphoma is a type of cancer
Maria
No.Lymphoma is not any type of cancer.....
Vivek
simple lymph is a tissue fluid less in plasma proteins which produces during tissue filteration...
Khawaja
lymphoma is a lymphatic cancer either Hodgkin's lymphoma & non Hodgkin's lymphoma..
Khawaja
Yes lymphoma is a lymphatic cancer
Loving

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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