Pectoralis minor muscle

What is Pectoralis minor muscle?

The pectoralis minor is triangular in shape and is under the pectoralis major. Together, they make up the axilla’s anterior wall. Together with other chest muscles, it works various movements of the scapula and can also work as an accessory muscle of respiration.

Origin

From the anterior third to fifth ribs, fleshy slips form the base of the pectoralis minor, close to the costal cartilage. Varieties at the beginning of the muscle are normal.

Insertion

The triangle’s apex is inserted into the medial border and upper surface of the scapula’s coracoid process.

Relations

The pectoralis major muscle, which is located close to the pectoralis minor and almost completely covers it, is the primary anterior relation. The lateral pectoral nerve and the pectoral branches of the thoracoacromial artery are situated in the space between the two muscles. Another layer of connective tissue, clavicopectoral fascia, is deep beneath the pectoralis major and it’s covering the fascia. It forms the suspensory ligament of the axilla, which is continuous with the axillary fascia, below the pectoralis minor and forms a fascial layer known as the costocoracoid membrane above it. The anterior wall of the axilla is framed by the pectoralis major and minor, as well as their related fascia.

The serratus anterior and intercostal muscles, the ribs, and several neurovascular and lymphatic structures are all posteriorly related to the pectoralis minor.

Due to the structures below or deep within the muscle and its tendon, the pectoralis minor is an important clinical and surgical landmark. The blood supply to the upper limb and the nerves that run deep to the pectoralis minor muscle:

the axillary artery and vein, as well as the posterior, lateral, and medial cords of the brachial plexus. The first section of the axillary vein runs medially to the medial edge of the pectoralis minor. The second section runs straight back to the muscle, and the third section of the axillary artery runs horizontally to the parallel line of the muscle.

Innervation

The medial pectoral nerve (C8, T1), one of the minor branches of the brachial plexus that originates from the cervical portion of the spinal cord, provides the pectoralis minor muscle with its primary nerve supply. The lateral pectoral nerve also supplies the pectoralis minor with innervation through a communicating branch known as the “ansa pectoralis,” which is typically located anterior to the first part of the axillary artery. As a result, the spinal roots of C5-T1 provide the pectoralis minor with innervation.

Blood supply

The vascular supply to the pectoralis minor comes from a few sources:

The pectoral and deltoid supplying branches are provided by the thoracoacromial artery, which is the second branch of an axillary artery.
The superior thoracic artery is a branch of an axillary artery.
The branch of the axillary artery is known as the lateral thoracic artery.

Function

The majority of the Pectoralis muscle’s functions are related to the scapula’s movement.

It moves the scapula laterally and anteriorly against the ribcage, acting in conjunction with the serratus anterior. When moving the arm forward, this action is essential.
The pectoralis minor exerts a force on the coracoid process, which pulls the lateral aspect of the scapula inferiorly while the levator scapulae and rhomboids pull upwards on the medial side of the rotation axis to achieve medial or downward rotation (the inferior angle of the scapula moves medially).
The pectoralis minor and serratus anterior muscles asset in the action of scapula depression when additional force is required. Scapula depression can typically be accomplished by gravity alone.
The pectoralis minor can be thought of as an accessory muscle of respiration during deep, forced inspiration when the scapula is fixed. During inspiration, it will help raise the ribs 3-5 and help expand the thoracic cavity.

Clinical implications of the pectoralis minor dysfunction

The pectoralis minor muscle can be interfered with in its ability to function properly by engaging in excessive sedentary activities that hurt good upper body posture. Keep in mind that this muscle acts on the scapula via the coracoid process, pulling it inferiorly and forward. Additionally, it causes the scapula to protrude and rotates the inferior glenoid cavity. The pectoralis minor muscle will compress in postures with prolonged scapular protraction, keeping the scapula in an uncomfortable position. As a result, pectoralis minor may be associated with several clinical conditions.

Impingement syndrome

Full abduction of the arm (180 degrees) is a consequence of development happening at two joints. The glenohumeral joint has a degree of abduction of 120 degrees. The scapula’s rotation on the posterior thoracic wall, also known as the scapulothoracic joint, accounts for the remaining 60 degrees. If these 60 levels of a turn are restricted or lost totally, moving the shoulder into full abduction can cause discomfort or pain.

The glenohumeral joint’s soft tissue structures (the supraspinatus tendon, subacromial bursa, and joint capsule) are being pinched between two bony surfaces, causing the pain. the greater tubercle of the humerus and the scapula’s acromion process. When shortened, the pectoralis minor muscle rotates the glenoid cavity inferiorly. As a result, the scapula may not be able to fully rotate in the opposite direction, superiorly, allowing for full abduction. Impingement could cause a soft tissue injury as a result of this limitation on abduction.

Thoracic outlet syndrome (TOS)

Compression or irritation of the neurovascular structures that supply the upper limb is the cause of this syndrome. The subclavian and axillary arteries and veins, in addition to the brachial plexus, are examples of these blood vessels. The compression of these structures in three areas has historically been linked to TOS:

between the first rib and the muscles of the anterior and middle scalene
underneath the clavicle;
between the pectoralis minor tendon and the coracoid process, in the subcoracoid space.
Pectoralis minor has only recently been found to be involved in cases of TOS, despite this third compression site. Treatment of neurovascular symptoms in the arm and hand, including pectoralis minor, should begin with the elimination of other more serious causes due to the muscle’s proximity to these structures, and tend to shorten with poor posture.

Trigger points

The referred pain patterns of trigger points in the pectoralis minor muscle and the pectoralis major muscle are nearly identical. These aggravation designs start toward the front of the shoulder and can reach out down within the arm, elbow, lower arm, and palm, and into the pinky, ring, and center fingers. Pain, numbness, and tingling in the arm and hand can also result from tension in the pectoralis minor muscle entangling armpit nerves.

Assessment

Palpation

Place a finger in the axilla and press obliquely toward the coracoid process of the scapula to palpate the pectoralis minor muscle. The muscle is in spasm if it hurts.

Strength

Patient position: Lying supine

Action: The examiner applies resistance to the coracoid process as the patient moves their arm to the side and pushes their coracoid process forward.
Gravity eliminate position: Seating

Length

Position: The patient is lying in a supine position with their arms by their sides, palms facing upward, knees bent, and lower back flat on the table.

Test: Standing at the head of the table, the examiner checks the shoulder girdle’s position. How much snugness is estimated by the degree to which the shoulder is raised from the table and by how much protection from descending strain on the shoulder Snugness might be recorded as slight, moderate, or checked

Pectoralis minor muscle stretching

The biceps brachii muscle is stretched here. Begin by raising your arm close to you to assume level generally. Anchor the wrist against a doorframe, squat rack, or wall with the palm facing downward. If you want to feel a stretch in your biceps muscle, twist away from the anchor point.

Pectoralis minor muscle strengthening exercise

Pectoralis active massage or PEC massage

The chest muscles can be massaged using this self-massage technique. Lean forward against a doorframe in a doorway or stable pole with a massage ball on a tender spot. Slowly perform a reverse fly motion while keeping your arm raised to shoulder height. As you complete a reverse fly, raise your arm at various angles to target multiple ranges. Try to stay within the maximum acceptable range. Limit self-rub methods to 2-3 minutes per day, and a limit of every other day.

Stability ball pec fly or chest fly

Using a Swiss ball, this chest-strengthening exercise increases anti-rotational core demand. Make sure the ball is supporting your neck and upper back as you lie down on it. Press two dumbbells up until your hands are straight above your shoulders while holding them at the level of your lower chest. For your comfort, you can bend your elbows slightly. Gradually lower your hands towards the floor by spreading them outwards while keeping them following your chest on a level plane. Pull your hands back up and up until you are back in the starting position.

Stability ball alternating chest press

Using a Swiss ball, this chest-strengthening exercise increases anti-rotational core demand. Make sure the ball is supporting your neck and upper back as you lie down on it. Press two dumbbells up until your hands are straight above your shoulders while holding them at the level of your lower chest. Throughout the entire movement, keep your wrist stacked directly above your elbows. To complete a repetition, lower one weight back to your lower chest and then back up. Repeat as necessary on both sides.

Stability ball chest press

Using a Swiss ball, this chest-strengthening exercise increases anti-rotational core demand. Make sure the ball is supporting your neck and upper back as you lie down on it. Press two dumbbells up until your hands are straight above your shoulders while holding them at the level of your lower chest. Throughout the entire movement, keep your wrist stacked directly above your elbows. To finish a repetition, lower the weight back down to your lower chest.

Plate squeeze front press

This is a strengthening exercise that involves simultaneously performing shoulder flexion and horizontal adduction. You can use two dumbbells instead of two weight plates in this version, which requires two weight plates. To prevent them from falling apart, hold the two plates or dumbbells in your hands and squeeze them together. To hold the weight straight out in front of you, raise the weights to chest height and extend your elbows. Hold for up to five seconds, then do it again as needed.

Incline pushups

The incline pushup is a less strenuous variation of the standard pushup. To gradually progress to a full pushup, this exercise is used. Begin by putting your hands on a seat or other raised surface like your sofa or bed. Maintain a straight spine as you slowly lower your body. At the end of the movement, your hands should typically be at your nipple line. Push up while bracing your core.

Archer push up

The Push Up exercise is the basis for this exercise progression. The goal of this exercise is to gradually advance to a full single-arm pushup. Begin by putting your hands on the floor more extensively than shoulder distance separated. The balls of your toes can help support your lower body (use anti-slip flooring to keep your feet stable). Maintain a neutral spine as you slowly lower the body while simultaneously extending one arm in front of you and leaning toward it. You can look at your extended arm by rotating your head. In most cases, at the bottom of the movement, your non-sliding hand should be at your nipple line. Push up while keeping the core braced and pulling the outstretched arm back in.

Knee push-up overhead slide

The Push Up exercise has been regressed here. To gradually progress to a full pushup, this exercise is used. Begin by putting your hands on the floor more extensively than shoulder distance separated. Put one hand on a slider disc or a towel for support. Your knees should be used to support your lower body (use padding on the flooring to alleviate knee pressure). Maintain a neutral spine as you slowly lower your body and simultaneously slide one hand overhead. In most cases, at the bottom of the movement, your non-sliding hand should be at your nipple line. While keeping the core braced and pulling the arm back in, push up.

Push up

This exercise uses the body’s weight as resistance to strengthen the chest and core. Begin by putting your hands on the floor more extensively than shoulder distance separated. The balls of your toes can help support your lower body. Maintain a straight spine as you slowly lower your body. At the end of the movement, your hands should typically be at your nipple line. Push up while bracing your core.

Knee push up or half push up

The Push Up exercise has been regressed here. To gradually progress to a full pushup, this exercise is used. Begin by putting your hands on the floor more extensively than shoulder distance separated. Your knees should be used to support your lower body (use padding on the flooring to alleviate knee pressure). Maintain a straight spine as you slowly lower your body. At the end of the movement, your hands should typically be at your nipple line. Push up while bracing your core.

Incline chest fly

The upper part of the chest is the focus of this strengthening exercise. You can perform this exercise with barbells, dumbbells, or a cable pulley system. Sit down on a bench with an angle of 35-45 degrees. Lift the weights to a height above your upper chest while lying on your back. For greater comfort, keep the elbows slightly bent. Gradually lower your hands towards the floor by spreading them outwards while keeping them following your upper chest evenly. Pull your hands back up and up until you are back in the starting position.

Bridge press

A hip bridge is used in this modified floor press exercise to allow for a decline bench press position. Begin by lying down on the floor while holding two weights. Stand firm on the top footing of a glute scaffold and press two hands upwards. Keep your elbows and hands parallel to your lower chest. To keep a neutral spine, brace the core. You can use dumbbells or kettlebells for this exercise.

Floor press

This is a relapsed practice rendition of the seat press. The reduced range of motion makes this exercise easier. With the weights in your hands, lie down on the floor. Start with your hands raised high enough to be above your chest. Keep the wrists in an upward direction following your elbows and lower your arm to the ground until your elbows contact the floor. Your hands will be roughly parallel to your chest’s bottom at the end of the movement. Repeat as necessary by pressing upwards to return to the starting position.

Pullup assist band serratus punch

This is a scapular protraction practice that utilizes a pull-up help band. Anchor one end of the band to a stable object behind you to get started. Hold the opposite end with a straight hand before you with your arm raised to 90 degrees shoulder flexion. By extending the shoulder blade (moving it forward), push the band forwards while maintaining a neutral thoracic spine and straight arm.

Foam roller ITWs

This is a mobility exercise for the upper back, chest, and shoulders. Place your body on a foam roller that is in line with your spine and lie down. Take three to five deep breaths as you raise your arms overhead in a Y shape. Concentrate on relaxing the chest and shoulder muscles. Recount for the T position (arms directly to the sides) and W position (arms swiped 45 degrees and pivoted inside into a displeasure position).

Push-up overhead slide

The Push Up exercise is the basis for this exercise progression. The goal of this exercise is to gradually advance to a full single-arm pushup. Begin by putting your hands on the floor more extensively than shoulder distance separated. Put one hand on a slider disc or a towel for support. The balls of your toes can help support your lower body (use anti-slip flooring to keep your feet stable). Maintain a neutral spine as you slowly lower your body and simultaneously slide one hand overhead. In most cases, at the bottom of the movement, your non-sliding hand should be at your nipple line. While keeping the core braced and pulling the arm back in, push up.

Pseudo planche puch up

This is a changed push-up workout. Put your hands on the floor at the level of your lower chest to begin. Place your hands in a way that rotates your wrist so that the fingers point toward your toes. Utilizing this modified hand orientation, complete a push-up. Make certain to keep the center propped to keep an unbiased spine during the activity.

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